rx/dist/rx.js

// Copyright (c) Microsoft, All rights reserved. See License.txt in the project root for license information.

;(function (undefined) {

  var objectTypes = {
    'function': true,
    'object': true
  };

  function checkGlobal(value) {
    return (value && value.Object === Object) ? value : null;
  }

  var freeExports = (objectTypes[typeof exports] && exports && !exports.nodeType) ? exports : null;
  var freeModule = (objectTypes[typeof module] && module && !module.nodeType) ? module : null;
  var freeGlobal = checkGlobal(freeExports && freeModule && typeof global === 'object' && global);
  var freeSelf = checkGlobal(objectTypes[typeof self] && self);
  var freeWindow = checkGlobal(objectTypes[typeof window] && window);
  var moduleExports = (freeModule && freeModule.exports === freeExports) ? freeExports : null;
  var thisGlobal = checkGlobal(objectTypes[typeof this] && this);
  var root = freeGlobal || ((freeWindow !== (thisGlobal && thisGlobal.window)) && freeWindow) || freeSelf || thisGlobal || Function('return this')();

  var Rx = {
    internals: {},
    config: {
      Promise: root.Promise
    },
    helpers: { }
  };

  // Defaults
  var noop = Rx.helpers.noop = function () { },
    identity = Rx.helpers.identity = function (x) { return x; },
    defaultNow = Rx.helpers.defaultNow = Date.now,
    defaultComparer = Rx.helpers.defaultComparer = function (x, y) { return isEqual(x, y); },
    defaultSubComparer = Rx.helpers.defaultSubComparer = function (x, y) { return x > y ? 1 : (x < y ? -1 : 0); },
    defaultKeySerializer = Rx.helpers.defaultKeySerializer = function (x) { return x.toString(); },
    defaultError = Rx.helpers.defaultError = function (err) { throw err; },
    isPromise = Rx.helpers.isPromise = function (p) { return !!p && typeof p.subscribe !== 'function' && typeof p.then === 'function'; },
    isFunction = Rx.helpers.isFunction = (function () {

      var isFn = function (value) {
        return typeof value == 'function' || false;
      };

      // fallback for older versions of Chrome and Safari
      if (isFn(/x/)) {
        isFn = function(value) {
          return typeof value == 'function' && toString.call(value) == '[object Function]';
        };
      }

      return isFn;
    }());

  function cloneArray(arr) { for(var a = [], i = 0, len = arr.length; i < len; i++) { a.push(arr[i]); } return a;}

  var errorObj = {e: {}};
  
  function tryCatcherGen(tryCatchTarget) {
    return function tryCatcher() {
      try {
        return tryCatchTarget.apply(this, arguments);
      } catch (e) {
        errorObj.e = e;
        return errorObj;
      }
    };
  }

  var tryCatch = Rx.internals.tryCatch = function tryCatch(fn) {
    if (!isFunction(fn)) { throw new TypeError('fn must be a function'); }
    return tryCatcherGen(fn);
  };

  function thrower(e) {
    throw e;
  }

  Rx.config.longStackSupport = false;
  var hasStacks = false, stacks = tryCatch(function () { throw new Error(); })();
  hasStacks = !!stacks.e && !!stacks.e.stack;

  // All code after this point will be filtered from stack traces reported by RxJS
  var rStartingLine = captureLine(), rFileName;

  var STACK_JUMP_SEPARATOR = 'From previous event:';

  function makeStackTraceLong(error, observable) {
    // If possible, transform the error stack trace by removing Node and RxJS
    // cruft, then concatenating with the stack trace of `observable`.
    if (hasStacks &&
        observable.stack &&
        typeof error === 'object' &&
        error !== null &&
        error.stack &&
        error.stack.indexOf(STACK_JUMP_SEPARATOR) === -1
    ) {
      var stacks = [];
      for (var o = observable; !!o; o = o.source) {
        if (o.stack) {
          stacks.unshift(o.stack);
        }
      }
      stacks.unshift(error.stack);

      var concatedStacks = stacks.join('\n' + STACK_JUMP_SEPARATOR + '\n');
      error.stack = filterStackString(concatedStacks);
    }
  }

  function filterStackString(stackString) {
    var lines = stackString.split('\n'), desiredLines = [];
    for (var i = 0, len = lines.length; i < len; i++) {
      var line = lines[i];

      if (!isInternalFrame(line) && !isNodeFrame(line) && line) {
        desiredLines.push(line);
      }
    }
    return desiredLines.join('\n');
  }

  function isInternalFrame(stackLine) {
    var fileNameAndLineNumber = getFileNameAndLineNumber(stackLine);
    if (!fileNameAndLineNumber) {
      return false;
    }
    var fileName = fileNameAndLineNumber[0], lineNumber = fileNameAndLineNumber[1];

    return fileName === rFileName &&
      lineNumber >= rStartingLine &&
      lineNumber <= rEndingLine;
  }

  function isNodeFrame(stackLine) {
    return stackLine.indexOf('(module.js:') !== -1 ||
      stackLine.indexOf('(node.js:') !== -1;
  }

  function captureLine() {
    if (!hasStacks) { return; }

    try {
      throw new Error();
    } catch (e) {
      var lines = e.stack.split('\n');
      var firstLine = lines[0].indexOf('@') > 0 ? lines[1] : lines[2];
      var fileNameAndLineNumber = getFileNameAndLineNumber(firstLine);
      if (!fileNameAndLineNumber) { return; }

      rFileName = fileNameAndLineNumber[0];
      return fileNameAndLineNumber[1];
    }
  }

  function getFileNameAndLineNumber(stackLine) {
    // Named functions: 'at functionName (filename:lineNumber:columnNumber)'
    var attempt1 = /at .+ \((.+):(\d+):(?:\d+)\)$/.exec(stackLine);
    if (attempt1) { return [attempt1[1], Number(attempt1[2])]; }

    // Anonymous functions: 'at filename:lineNumber:columnNumber'
    var attempt2 = /at ([^ ]+):(\d+):(?:\d+)$/.exec(stackLine);
    if (attempt2) { return [attempt2[1], Number(attempt2[2])]; }

    // Firefox style: 'function@filename:lineNumber or @filename:lineNumber'
    var attempt3 = /.*@(.+):(\d+)$/.exec(stackLine);
    if (attempt3) { return [attempt3[1], Number(attempt3[2])]; }
  }

  var EmptyError = Rx.EmptyError = function() {
    this.message = 'Sequence contains no elements.';
    Error.call(this);
  };
  EmptyError.prototype = Object.create(Error.prototype);
  EmptyError.prototype.name = 'EmptyError';

  var ObjectDisposedError = Rx.ObjectDisposedError = function() {
    this.message = 'Object has been disposed';
    Error.call(this);
  };
  ObjectDisposedError.prototype = Object.create(Error.prototype);
  ObjectDisposedError.prototype.name = 'ObjectDisposedError';

  var ArgumentOutOfRangeError = Rx.ArgumentOutOfRangeError = function () {
    this.message = 'Argument out of range';
    Error.call(this);
  };
  ArgumentOutOfRangeError.prototype = Object.create(Error.prototype);
  ArgumentOutOfRangeError.prototype.name = 'ArgumentOutOfRangeError';

  var NotSupportedError = Rx.NotSupportedError = function (message) {
    this.message = message || 'This operation is not supported';
    Error.call(this);
  };
  NotSupportedError.prototype = Object.create(Error.prototype);
  NotSupportedError.prototype.name = 'NotSupportedError';

  var NotImplementedError = Rx.NotImplementedError = function (message) {
    this.message = message || 'This operation is not implemented';
    Error.call(this);
  };
  NotImplementedError.prototype = Object.create(Error.prototype);
  NotImplementedError.prototype.name = 'NotImplementedError';

  var notImplemented = Rx.helpers.notImplemented = function () {
    throw new NotImplementedError();
  };

  var notSupported = Rx.helpers.notSupported = function () {
    throw new NotSupportedError();
  };

  // Shim in iterator support
  var $iterator$ = (typeof Symbol === 'function' && Symbol.iterator) ||
    '_es6shim_iterator_';
  // Bug for mozilla version
  if (root.Set && typeof new root.Set()['@@iterator'] === 'function') {
    $iterator$ = '@@iterator';
  }

  var doneEnumerator = Rx.doneEnumerator = { done: true, value: undefined };

  var isIterable = Rx.helpers.isIterable = function (o) {
    return o && o[$iterator$] !== undefined;
  };

  var isArrayLike = Rx.helpers.isArrayLike = function (o) {
    return o && o.length !== undefined;
  };

  Rx.helpers.iterator = $iterator$;

  var bindCallback = Rx.internals.bindCallback = function (func, thisArg, argCount) {
    if (typeof thisArg === 'undefined') { return func; }
    switch(argCount) {
      case 0:
        return function() {
          return func.call(thisArg)
        };
      case 1:
        return function(arg) {
          return func.call(thisArg, arg);
        };
      case 2:
        return function(value, index) {
          return func.call(thisArg, value, index);
        };
      case 3:
        return function(value, index, collection) {
          return func.call(thisArg, value, index, collection);
        };
    }

    return function() {
      return func.apply(thisArg, arguments);
    };
  };

  /** Used to determine if values are of the language type Object */
  var dontEnums = ['toString',
    'toLocaleString',
    'valueOf',
    'hasOwnProperty',
    'isPrototypeOf',
    'propertyIsEnumerable',
    'constructor'],
  dontEnumsLength = dontEnums.length;

var argsTag = '[object Arguments]',
    arrayTag = '[object Array]',
    boolTag = '[object Boolean]',
    dateTag = '[object Date]',
    errorTag = '[object Error]',
    funcTag = '[object Function]',
    mapTag = '[object Map]',
    numberTag = '[object Number]',
    objectTag = '[object Object]',
    regexpTag = '[object RegExp]',
    setTag = '[object Set]',
    stringTag = '[object String]',
    weakMapTag = '[object WeakMap]';

var arrayBufferTag = '[object ArrayBuffer]',
    float32Tag = '[object Float32Array]',
    float64Tag = '[object Float64Array]',
    int8Tag = '[object Int8Array]',
    int16Tag = '[object Int16Array]',
    int32Tag = '[object Int32Array]',
    uint8Tag = '[object Uint8Array]',
    uint8ClampedTag = '[object Uint8ClampedArray]',
    uint16Tag = '[object Uint16Array]',
    uint32Tag = '[object Uint32Array]';

var typedArrayTags = {};
typedArrayTags[float32Tag] = typedArrayTags[float64Tag] =
typedArrayTags[int8Tag] = typedArrayTags[int16Tag] =
typedArrayTags[int32Tag] = typedArrayTags[uint8Tag] =
typedArrayTags[uint8ClampedTag] = typedArrayTags[uint16Tag] =
typedArrayTags[uint32Tag] = true;
typedArrayTags[argsTag] = typedArrayTags[arrayTag] =
typedArrayTags[arrayBufferTag] = typedArrayTags[boolTag] =
typedArrayTags[dateTag] = typedArrayTags[errorTag] =
typedArrayTags[funcTag] = typedArrayTags[mapTag] =
typedArrayTags[numberTag] = typedArrayTags[objectTag] =
typedArrayTags[regexpTag] = typedArrayTags[setTag] =
typedArrayTags[stringTag] = typedArrayTags[weakMapTag] = false;

var objectProto = Object.prototype,
    hasOwnProperty = objectProto.hasOwnProperty,
    objToString = objectProto.toString,
    MAX_SAFE_INTEGER = Math.pow(2, 53) - 1;

var keys = Object.keys || (function() {
    var hasOwnProperty = Object.prototype.hasOwnProperty,
        hasDontEnumBug = !({ toString: null }).propertyIsEnumerable('toString'),
        dontEnums = [
          'toString',
          'toLocaleString',
          'valueOf',
          'hasOwnProperty',
          'isPrototypeOf',
          'propertyIsEnumerable',
          'constructor'
        ],
        dontEnumsLength = dontEnums.length;

    return function(obj) {
      if (typeof obj !== 'object' && (typeof obj !== 'function' || obj === null)) {
        throw new TypeError('Object.keys called on non-object');
      }

      var result = [], prop, i;

      for (prop in obj) {
        if (hasOwnProperty.call(obj, prop)) {
          result.push(prop);
        }
      }

      if (hasDontEnumBug) {
        for (i = 0; i < dontEnumsLength; i++) {
          if (hasOwnProperty.call(obj, dontEnums[i])) {
            result.push(dontEnums[i]);
          }
        }
      }
      return result;
    };
  }());

function equalObjects(object, other, equalFunc, isLoose, stackA, stackB) {
  var objProps = keys(object),
      objLength = objProps.length,
      othProps = keys(other),
      othLength = othProps.length;

  if (objLength !== othLength && !isLoose) {
    return false;
  }
  var index = objLength, key;
  while (index--) {
    key = objProps[index];
    if (!(isLoose ? key in other : hasOwnProperty.call(other, key))) {
      return false;
    }
  }
  var skipCtor = isLoose;
  while (++index < objLength) {
    key = objProps[index];
    var objValue = object[key],
        othValue = other[key],
        result;

    if (!(result === undefined ? equalFunc(objValue, othValue, isLoose, stackA, stackB) : result)) {
      return false;
    }
    skipCtor || (skipCtor = key === 'constructor');
  }
  if (!skipCtor) {
    var objCtor = object.constructor,
        othCtor = other.constructor;

    if (objCtor !== othCtor &&
        ('constructor' in object && 'constructor' in other) &&
        !(typeof objCtor === 'function' && objCtor instanceof objCtor &&
          typeof othCtor === 'function' && othCtor instanceof othCtor)) {
      return false;
    }
  }
  return true;
}

function equalByTag(object, other, tag) {
  switch (tag) {
    case boolTag:
    case dateTag:
      return +object === +other;

    case errorTag:
      return object.name === other.name && object.message === other.message;

    case numberTag:
      return (object !== +object) ?
        other !== +other :
        object === +other;

    case regexpTag:
    case stringTag:
      return object === (other + '');
  }
  return false;
}

var isObject = Rx.internals.isObject = function(value) {
  var type = typeof value;
  return !!value && (type === 'object' || type === 'function');
};

function isObjectLike(value) {
  return !!value && typeof value === 'object';
}

function isLength(value) {
  return typeof value === 'number' && value > -1 && value % 1 === 0 && value <= MAX_SAFE_INTEGER;
}

var isHostObject = (function() {
  try {
    Object({ 'toString': 0 } + '');
  } catch(e) {
    return function() { return false; };
  }
  return function(value) {
    return typeof value.toString !== 'function' && typeof (value + '') === 'string';
  };
}());

function isTypedArray(value) {
  return isObjectLike(value) && isLength(value.length) && !!typedArrayTags[objToString.call(value)];
}

var isArray = Array.isArray || function(value) {
  return isObjectLike(value) && isLength(value.length) && objToString.call(value) === arrayTag;
};

function arraySome (array, predicate) {
  var index = -1,
      length = array.length;

  while (++index < length) {
    if (predicate(array[index], index, array)) {
      return true;
    }
  }
  return false;
}

function equalArrays(array, other, equalFunc, isLoose, stackA, stackB) {
  var index = -1,
      arrLength = array.length,
      othLength = other.length;

  if (arrLength !== othLength && !(isLoose && othLength > arrLength)) {
    return false;
  }
  // Ignore non-index properties.
  while (++index < arrLength) {
    var arrValue = array[index],
        othValue = other[index],
        result;

    if (result !== undefined) {
      if (result) {
        continue;
      }
      return false;
    }
    // Recursively compare arrays (susceptible to call stack limits).
    if (isLoose) {
      if (!arraySome(other, function(othValue) {
            return arrValue === othValue || equalFunc(arrValue, othValue, isLoose, stackA, stackB);
          })) {
        return false;
      }
    } else if (!(arrValue === othValue || equalFunc(arrValue, othValue, isLoose, stackA, stackB))) {
      return false;
    }
  }
  return true;
}

function baseIsEqualDeep(object, other, equalFunc, isLoose, stackA, stackB) {
  var objIsArr = isArray(object),
      othIsArr = isArray(other),
      objTag = arrayTag,
      othTag = arrayTag;

  if (!objIsArr) {
    objTag = objToString.call(object);
    if (objTag === argsTag) {
      objTag = objectTag;
    } else if (objTag !== objectTag) {
      objIsArr = isTypedArray(object);
    }
  }
  if (!othIsArr) {
    othTag = objToString.call(other);
    if (othTag === argsTag) {
      othTag = objectTag;
    }
  }
  var objIsObj = objTag === objectTag && !isHostObject(object),
      othIsObj = othTag === objectTag && !isHostObject(other),
      isSameTag = objTag === othTag;

  if (isSameTag && !(objIsArr || objIsObj)) {
    return equalByTag(object, other, objTag);
  }
  if (!isLoose) {
    var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
        othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');

    if (objIsWrapped || othIsWrapped) {
      return equalFunc(objIsWrapped ? object.value() : object, othIsWrapped ? other.value() : other, isLoose, stackA, stackB);
    }
  }
  if (!isSameTag) {
    return false;
  }
  // Assume cyclic values are equal.
  // For more information on detecting circular references see https://es5.github.io/#JO.
  stackA || (stackA = []);
  stackB || (stackB = []);

  var length = stackA.length;
  while (length--) {
    if (stackA[length] === object) {
      return stackB[length] === other;
    }
  }
  // Add `object` and `other` to the stack of traversed objects.
  stackA.push(object);
  stackB.push(other);

  var result = (objIsArr ? equalArrays : equalObjects)(object, other, equalFunc, isLoose, stackA, stackB);

  stackA.pop();
  stackB.pop();

  return result;
}

function baseIsEqual(value, other, isLoose, stackA, stackB) {
  if (value === other) {
    return true;
  }
  if (value == null || other == null || (!isObject(value) && !isObjectLike(other))) {
    return value !== value && other !== other;
  }
  return baseIsEqualDeep(value, other, baseIsEqual, isLoose, stackA, stackB);
}

var isEqual = Rx.internals.isEqual = function (value, other) {
  return baseIsEqual(value, other);
};

  var hasProp = {}.hasOwnProperty,
      slice = Array.prototype.slice;

  var inherits = Rx.internals.inherits = function (child, parent) {
    function __() { this.constructor = child; }
    __.prototype = parent.prototype;
    child.prototype = new __();
  };

  var addProperties = Rx.internals.addProperties = function (obj) {
    for(var sources = [], i = 1, len = arguments.length; i < len; i++) { sources.push(arguments[i]); }
    for (var idx = 0, ln = sources.length; idx < ln; idx++) {
      var source = sources[idx];
      for (var prop in source) {
        obj[prop] = source[prop];
      }
    }
  };

  // Rx Utils
  var addRef = Rx.internals.addRef = function (xs, r) {
    return new AnonymousObservable(function (observer) {
      return new BinaryDisposable(r.getDisposable(), xs.subscribe(observer));
    });
  };

  function arrayInitialize(count, factory) {
    var a = new Array(count);
    for (var i = 0; i < count; i++) {
      a[i] = factory();
    }
    return a;
  }

  /**
   * Represents a group of disposable resources that are disposed together.
   * @constructor
   */
  var CompositeDisposable = Rx.CompositeDisposable = function () {
    var args = [], i, len;
    if (Array.isArray(arguments[0])) {
      args = arguments[0];
    } else {
      len = arguments.length;
      args = new Array(len);
      for(i = 0; i < len; i++) { args[i] = arguments[i]; }
    }
    this.disposables = args;
    this.isDisposed = false;
    this.length = args.length;
  };

  var CompositeDisposablePrototype = CompositeDisposable.prototype;

  /**
   * Adds a disposable to the CompositeDisposable or disposes the disposable if the CompositeDisposable is disposed.
   * @param {Mixed} item Disposable to add.
   */
  CompositeDisposablePrototype.add = function (item) {
    if (this.isDisposed) {
      item.dispose();
    } else {
      this.disposables.push(item);
      this.length++;
    }
  };

  /**
   * Removes and disposes the first occurrence of a disposable from the CompositeDisposable.
   * @param {Mixed} item Disposable to remove.
   * @returns {Boolean} true if found; false otherwise.
   */
  CompositeDisposablePrototype.remove = function (item) {
    var shouldDispose = false;
    if (!this.isDisposed) {
      var idx = this.disposables.indexOf(item);
      if (idx !== -1) {
        shouldDispose = true;
        this.disposables.splice(idx, 1);
        this.length--;
        item.dispose();
      }
    }
    return shouldDispose;
  };

  /**
   *  Disposes all disposables in the group and removes them from the group.
   */
  CompositeDisposablePrototype.dispose = function () {
    if (!this.isDisposed) {
      this.isDisposed = true;
      var len = this.disposables.length, currentDisposables = new Array(len);
      for(var i = 0; i < len; i++) { currentDisposables[i] = this.disposables[i]; }
      this.disposables = [];
      this.length = 0;

      for (i = 0; i < len; i++) {
        currentDisposables[i].dispose();
      }
    }
  };

  /**
   * Provides a set of static methods for creating Disposables.
   * @param {Function} dispose Action to run during the first call to dispose. The action is guaranteed to be run at most once.
   */
  var Disposable = Rx.Disposable = function (action) {
    this.isDisposed = false;
    this.action = action || noop;
  };

  /** Performs the task of cleaning up resources. */
  Disposable.prototype.dispose = function () {
    if (!this.isDisposed) {
      this.action();
      this.isDisposed = true;
    }
  };

  /**
   * Creates a disposable object that invokes the specified action when disposed.
   * @param {Function} dispose Action to run during the first call to dispose. The action is guaranteed to be run at most once.
   * @return {Disposable} The disposable object that runs the given action upon disposal.
   */
  var disposableCreate = Disposable.create = function (action) { return new Disposable(action); };

  /**
   * Gets the disposable that does nothing when disposed.
   */
  var disposableEmpty = Disposable.empty = { dispose: noop };

  /**
   * Validates whether the given object is a disposable
   * @param {Object} Object to test whether it has a dispose method
   * @returns {Boolean} true if a disposable object, else false.
   */
  var isDisposable = Disposable.isDisposable = function (d) {
    return d && isFunction(d.dispose);
  };

  var checkDisposed = Disposable.checkDisposed = function (disposable) {
    if (disposable.isDisposed) { throw new ObjectDisposedError(); }
  };

  var disposableFixup = Disposable._fixup = function (result) {
    return isDisposable(result) ? result : disposableEmpty;
  };

  // Single assignment
  var SingleAssignmentDisposable = Rx.SingleAssignmentDisposable = function () {
    this.isDisposed = false;
    this.current = null;
  };
  SingleAssignmentDisposable.prototype.getDisposable = function () {
    return this.current;
  };
  SingleAssignmentDisposable.prototype.setDisposable = function (value) {
    if (this.current) { throw new Error('Disposable has already been assigned'); }
    var shouldDispose = this.isDisposed;
    !shouldDispose && (this.current = value);
    shouldDispose && value && value.dispose();
  };
  SingleAssignmentDisposable.prototype.dispose = function () {
    if (!this.isDisposed) {
      this.isDisposed = true;
      var old = this.current;
      this.current = null;
      old && old.dispose();
    }
  };

  // Multiple assignment disposable
  var SerialDisposable = Rx.SerialDisposable = function () {
    this.isDisposed = false;
    this.current = null;
  };
  SerialDisposable.prototype.getDisposable = function () {
    return this.current;
  };
  SerialDisposable.prototype.setDisposable = function (value) {
    var shouldDispose = this.isDisposed;
    if (!shouldDispose) {
      var old = this.current;
      this.current = value;
    }
    old && old.dispose();
    shouldDispose && value && value.dispose();
  };
  SerialDisposable.prototype.dispose = function () {
    if (!this.isDisposed) {
      this.isDisposed = true;
      var old = this.current;
      this.current = null;
    }
    old && old.dispose();
  };

  var BinaryDisposable = Rx.BinaryDisposable = function (first, second) {
    this._first = first;
    this._second = second;
    this.isDisposed = false;
  };

  BinaryDisposable.prototype.dispose = function () {
    if (!this.isDisposed) {
      this.isDisposed = true;
      var old1 = this._first;
      this._first = null;
      old1 && old1.dispose();
      var old2 = this._second;
      this._second = null;
      old2 && old2.dispose();
    }
  };

  var NAryDisposable = Rx.NAryDisposable = function (disposables) {
    this._disposables = disposables;
    this.isDisposed = false;
  };

  NAryDisposable.prototype.dispose = function () {
    if (!this.isDisposed) {
      this.isDisposed = true;
      for (var i = 0, len = this._disposables.length; i < len; i++) {
        this._disposables[i].dispose();
      }
      this._disposables.length = 0;
    }
  };

  /**
   * Represents a disposable resource that only disposes its underlying disposable resource when all dependent disposable objects have been disposed.
   */
  var RefCountDisposable = Rx.RefCountDisposable = (function () {

    function InnerDisposable(disposable) {
      this.disposable = disposable;
      this.disposable.count++;
      this.isInnerDisposed = false;
    }

    InnerDisposable.prototype.dispose = function () {
      if (!this.disposable.isDisposed && !this.isInnerDisposed) {
        this.isInnerDisposed = true;
        this.disposable.count--;
        if (this.disposable.count === 0 && this.disposable.isPrimaryDisposed) {
          this.disposable.isDisposed = true;
          this.disposable.underlyingDisposable.dispose();
        }
      }
    };

    /**
     * Initializes a new instance of the RefCountDisposable with the specified disposable.
     * @constructor
     * @param {Disposable} disposable Underlying disposable.
      */
    function RefCountDisposable(disposable) {
      this.underlyingDisposable = disposable;
      this.isDisposed = false;
      this.isPrimaryDisposed = false;
      this.count = 0;
    }

    /**
     * Disposes the underlying disposable only when all dependent disposables have been disposed
     */
    RefCountDisposable.prototype.dispose = function () {
      if (!this.isDisposed && !this.isPrimaryDisposed) {
        this.isPrimaryDisposed = true;
        if (this.count === 0) {
          this.isDisposed = true;
          this.underlyingDisposable.dispose();
        }
      }
    };

    /**
     * Returns a dependent disposable that when disposed decreases the refcount on the underlying disposable.
     * @returns {Disposable} A dependent disposable contributing to the reference count that manages the underlying disposable's lifetime.
     */
    RefCountDisposable.prototype.getDisposable = function () {
      return this.isDisposed ? disposableEmpty : new InnerDisposable(this);
    };

    return RefCountDisposable;
  })();

  function ScheduledDisposable(scheduler, disposable) {
    this.scheduler = scheduler;
    this.disposable = disposable;
    this.isDisposed = false;
  }

  function scheduleItem(s, self) {
    if (!self.isDisposed) {
      self.isDisposed = true;
      self.disposable.dispose();
    }
  }

  ScheduledDisposable.prototype.dispose = function () {
    this.scheduler.schedule(this, scheduleItem);
  };

  var ScheduledItem = Rx.internals.ScheduledItem = function (scheduler, state, action, dueTime, comparer) {
    this.scheduler = scheduler;
    this.state = state;
    this.action = action;
    this.dueTime = dueTime;
    this.comparer = comparer || defaultSubComparer;
    this.disposable = new SingleAssignmentDisposable();
  };

  ScheduledItem.prototype.invoke = function () {
    this.disposable.setDisposable(this.invokeCore());
  };

  ScheduledItem.prototype.compareTo = function (other) {
    return this.comparer(this.dueTime, other.dueTime);
  };

  ScheduledItem.prototype.isCancelled = function () {
    return this.disposable.isDisposed;
  };

  ScheduledItem.prototype.invokeCore = function () {
    return disposableFixup(this.action(this.scheduler, this.state));
  };

  /** Provides a set of static properties to access commonly used schedulers. */
  var Scheduler = Rx.Scheduler = (function () {

    function Scheduler() { }

    /** Determines whether the given object is a scheduler */
    Scheduler.isScheduler = function (s) {
      return s instanceof Scheduler;
    };

    var schedulerProto = Scheduler.prototype;

    /**
   * Schedules an action to be executed.
   * @param state State passed to the action to be executed.
   * @param {Function} action Action to be executed.
   * @returns {Disposable} The disposable object used to cancel the scheduled action (best effort).
   */
    schedulerProto.schedule = function (state, action) {
      throw new NotImplementedError();
    };

  /**
   * Schedules an action to be executed after dueTime.
   * @param state State passed to the action to be executed.
   * @param {Function} action Action to be executed.
   * @param {Number} dueTime Relative time after which to execute the action.
   * @returns {Disposable} The disposable object used to cancel the scheduled action (best effort).
   */
    schedulerProto.scheduleFuture = function (state, dueTime, action) {
      var dt = dueTime;
      dt instanceof Date && (dt = dt - this.now());
      dt = Scheduler.normalize(dt);

      if (dt === 0) { return this.schedule(state, action); }

      return this._scheduleFuture(state, dt, action);
    };

    schedulerProto._scheduleFuture = function (state, dueTime, action) {
      throw new NotImplementedError();
    };

    /** Gets the current time according to the local machine's system clock. */
    Scheduler.now = defaultNow;

    /** Gets the current time according to the local machine's system clock. */
    Scheduler.prototype.now = defaultNow;

    /**
     * Normalizes the specified TimeSpan value to a positive value.
     * @param {Number} timeSpan The time span value to normalize.
     * @returns {Number} The specified TimeSpan value if it is zero or positive; otherwise, 0
     */
    Scheduler.normalize = function (timeSpan) {
      timeSpan < 0 && (timeSpan = 0);
      return timeSpan;
    };

    return Scheduler;
  }());

  var normalizeTime = Scheduler.normalize, isScheduler = Scheduler.isScheduler;

  (function (schedulerProto) {

    function invokeRecImmediate(scheduler, pair) {
      var state = pair[0], action = pair[1], group = new CompositeDisposable();
      action(state, innerAction);
      return group;

      function innerAction(state2) {
        var isAdded = false, isDone = false;

        var d = scheduler.schedule(state2, scheduleWork);
        if (!isDone) {
          group.add(d);
          isAdded = true;
        }

        function scheduleWork(_, state3) {
          if (isAdded) {
            group.remove(d);
          } else {
            isDone = true;
          }
          action(state3, innerAction);
          return disposableEmpty;
        }
      }
    }

    function invokeRecDate(scheduler, pair) {
      var state = pair[0], action = pair[1], group = new CompositeDisposable();
      action(state, innerAction);
      return group;

      function innerAction(state2, dueTime1) {
        var isAdded = false, isDone = false;

        var d = scheduler.scheduleFuture(state2, dueTime1, scheduleWork);
        if (!isDone) {
          group.add(d);
          isAdded = true;
        }

        function scheduleWork(_, state3) {
          if (isAdded) {
            group.remove(d);
          } else {
            isDone = true;
          }
          action(state3, innerAction);
          return disposableEmpty;
        }
      }
    }

    /**
     * Schedules an action to be executed recursively.
     * @param {Mixed} state State passed to the action to be executed.
     * @param {Function} action Action to execute recursively. The last parameter passed to the action is used to trigger recursive scheduling of the action, passing in recursive invocation state.
     * @returns {Disposable} The disposable object used to cancel the scheduled action (best effort).
     */
    schedulerProto.scheduleRecursive = function (state, action) {
      return this.schedule([state, action], invokeRecImmediate);
    };

    /**
     * Schedules an action to be executed recursively after a specified relative or absolute due time.
     * @param {Mixed} state State passed to the action to be executed.
     * @param {Function} action Action to execute recursively. The last parameter passed to the action is used to trigger recursive scheduling of the action, passing in the recursive due time and invocation state.
     * @param {Number | Date} dueTime Relative or absolute time after which to execute the action for the first time.
     * @returns {Disposable} The disposable object used to cancel the scheduled action (best effort).
     */
    schedulerProto.scheduleRecursiveFuture = function (state, dueTime, action) {
      return this.scheduleFuture([state, action], dueTime, invokeRecDate);
    };

  }(Scheduler.prototype));

  (function (schedulerProto) {

    /**
     * Schedules a periodic piece of work by dynamically discovering the scheduler's capabilities. The periodic task will be scheduled using window.setInterval for the base implementation.
     * @param {Mixed} state Initial state passed to the action upon the first iteration.
     * @param {Number} period Period for running the work periodically.
     * @param {Function} action Action to be executed, potentially updating the state.
     * @returns {Disposable} The disposable object used to cancel the scheduled recurring action (best effort).
     */
    schedulerProto.schedulePeriodic = function(state, period, action) {
      if (typeof root.setInterval === 'undefined') { throw new NotSupportedError(); }
      period = normalizeTime(period);
      var s = state, id = root.setInterval(function () { s = action(s); }, period);
      return disposableCreate(function () { root.clearInterval(id); });
    };

  }(Scheduler.prototype));

  (function (schedulerProto) {
    /**
     * Returns a scheduler that wraps the original scheduler, adding exception handling for scheduled actions.
     * @param {Function} handler Handler that's run if an exception is caught. The exception will be rethrown if the handler returns false.
     * @returns {Scheduler} Wrapper around the original scheduler, enforcing exception handling.
     */
    schedulerProto.catchError = schedulerProto['catch'] = function (handler) {
      return new CatchScheduler(this, handler);
    };
  }(Scheduler.prototype));

  var SchedulePeriodicRecursive = Rx.internals.SchedulePeriodicRecursive = (function () {
    function createTick(self) {
      return function tick(command, recurse) {
        recurse(0, self._period);
        var state = tryCatch(self._action)(self._state);
        if (state === errorObj) {
          self._cancel.dispose();
          thrower(state.e);
        }
        self._state = state;
      };
    }

    function SchedulePeriodicRecursive(scheduler, state, period, action) {
      this._scheduler = scheduler;
      this._state = state;
      this._period = period;
      this._action = action;
    }

    SchedulePeriodicRecursive.prototype.start = function () {
      var d = new SingleAssignmentDisposable();
      this._cancel = d;
      d.setDisposable(this._scheduler.scheduleRecursiveFuture(0, this._period, createTick(this)));

      return d;
    };

    return SchedulePeriodicRecursive;
  }());

  /** Gets a scheduler that schedules work immediately on the current thread. */
   var ImmediateScheduler = (function (__super__) {
    inherits(ImmediateScheduler, __super__);
    function ImmediateScheduler() {
      __super__.call(this);
    }

    ImmediateScheduler.prototype.schedule = function (state, action) {
      return disposableFixup(action(this, state));
    };

    return ImmediateScheduler;
  }(Scheduler));

  var immediateScheduler = Scheduler.immediate = new ImmediateScheduler();

  /**
   * Gets a scheduler that schedules work as soon as possible on the current thread.
   */
  var CurrentThreadScheduler = (function (__super__) {
    var queue;

    function runTrampoline () {
      while (queue.length > 0) {
        var item = queue.dequeue();
        !item.isCancelled() && item.invoke();
      }
    }

    inherits(CurrentThreadScheduler, __super__);
    function CurrentThreadScheduler() {
      __super__.call(this);
    }

    CurrentThreadScheduler.prototype.schedule = function (state, action) {
      var si = new ScheduledItem(this, state, action, this.now());

      if (!queue) {
        queue = new PriorityQueue(4);
        queue.enqueue(si);

        var result = tryCatch(runTrampoline)();
        queue = null;
        if (result === errorObj) { thrower(result.e); }
      } else {
        queue.enqueue(si);
      }
      return si.disposable;
    };

    CurrentThreadScheduler.prototype.scheduleRequired = function () { return !queue; };

    return CurrentThreadScheduler;
  }(Scheduler));

  var currentThreadScheduler = Scheduler.currentThread = new CurrentThreadScheduler();

  var scheduleMethod, clearMethod;

  var localTimer = (function () {
    var localSetTimeout, localClearTimeout = noop;
    if (!!root.setTimeout) {
      localSetTimeout = root.setTimeout;
      localClearTimeout = root.clearTimeout;
    } else if (!!root.WScript) {
      localSetTimeout = function (fn, time) {
        root.WScript.Sleep(time);
        fn();
      };
    } else {
      throw new NotSupportedError();
    }

    return {
      setTimeout: localSetTimeout,
      clearTimeout: localClearTimeout
    };
  }());
  var localSetTimeout = localTimer.setTimeout,
    localClearTimeout = localTimer.clearTimeout;

  (function () {

    var nextHandle = 1, tasksByHandle = {}, currentlyRunning = false;

    clearMethod = function (handle) {
      delete tasksByHandle[handle];
    };

    function runTask(handle) {
      if (currentlyRunning) {
        localSetTimeout(function () { runTask(handle); }, 0);
      } else {
        var task = tasksByHandle[handle];
        if (task) {
          currentlyRunning = true;
          var result = tryCatch(task)();
          clearMethod(handle);
          currentlyRunning = false;
          if (result === errorObj) { thrower(result.e); }
        }
      }
    }

    var reNative = new RegExp('^' +
      String(toString)
        .replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
        .replace(/toString| for [^\]]+/g, '.*?') + '$'
    );

    var setImmediate = typeof (setImmediate = freeGlobal && moduleExports && freeGlobal.setImmediate) == 'function' &&
      !reNative.test(setImmediate) && setImmediate;

    function postMessageSupported () {
      // Ensure not in a worker
      if (!root.postMessage || root.importScripts) { return false; }
      var isAsync = false, oldHandler = root.onmessage;
      // Test for async
      root.onmessage = function () { isAsync = true; };
      root.postMessage('', '*');
      root.onmessage = oldHandler;

      return isAsync;
    }

    // Use in order, setImmediate, nextTick, postMessage, MessageChannel, script readystatechanged, setTimeout
    if (isFunction(setImmediate)) {
      scheduleMethod = function (action) {
        var id = nextHandle++;
        tasksByHandle[id] = action;
        setImmediate(function () { runTask(id); });

        return id;
      };
    } else if (typeof process !== 'undefined' && {}.toString.call(process) === '[object process]') {
      scheduleMethod = function (action) {
        var id = nextHandle++;
        tasksByHandle[id] = action;
        process.nextTick(function () { runTask(id); });

        return id;
      };
    } else if (postMessageSupported()) {
      var MSG_PREFIX = 'ms.rx.schedule' + Math.random();

      var onGlobalPostMessage = function (event) {
        // Only if we're a match to avoid any other global events
        if (typeof event.data === 'string' && event.data.substring(0, MSG_PREFIX.length) === MSG_PREFIX) {
          runTask(event.data.substring(MSG_PREFIX.length));
        }
      };

      root.addEventListener('message', onGlobalPostMessage, false);

      scheduleMethod = function (action) {
        var id = nextHandle++;
        tasksByHandle[id] = action;
        root.postMessage(MSG_PREFIX + currentId, '*');
        return id;
      };
    } else if (!!root.MessageChannel) {
      var channel = new root.MessageChannel();

      channel.port1.onmessage = function (e) { runTask(e.data); };

      scheduleMethod = function (action) {
        var id = nextHandle++;
        tasksByHandle[id] = action;
        channel.port2.postMessage(id);
        return id;
      };
    } else if ('document' in root && 'onreadystatechange' in root.document.createElement('script')) {

      scheduleMethod = function (action) {
        var scriptElement = root.document.createElement('script');
        var id = nextHandle++;
        tasksByHandle[id] = action;

        scriptElement.onreadystatechange = function () {
          runTask(id);
          scriptElement.onreadystatechange = null;
          scriptElement.parentNode.removeChild(scriptElement);
          scriptElement = null;
        };
        root.document.documentElement.appendChild(scriptElement);
        return id;
      };

    } else {
      scheduleMethod = function (action) {
        var id = nextHandle++;
        tasksByHandle[id] = action;
        localSetTimeout(function () {
          runTask(id);
        }, 0);

        return id;
      };
    }
  }());

  /**
   * Gets a scheduler that schedules work via a timed callback based upon platform.
   */
   var DefaultScheduler = (function (__super__) {
     inherits(DefaultScheduler, __super__);
     function DefaultScheduler() {
       __super__.call(this);
     }

     function scheduleAction(disposable, action, scheduler, state) {
       return function schedule() {
         disposable.setDisposable(Disposable._fixup(action(scheduler, state)));
       };
     }

     function ClearDisposable(id) {
       this._id = id;
       this.isDisposed = false;
     }

     ClearDisposable.prototype.dispose = function () {
       if (!this.isDisposed) {
         this.isDisposed = true;
         clearMethod(this._id);
       }
     };

     function LocalClearDisposable(id) {
       this._id = id;
       this.isDisposed = false;
     }

     LocalClearDisposable.prototype.dispose = function () {
       if (!this.isDisposed) {
         this.isDisposed = true;
         localClearTimeout(this._id);
       }
     };

    DefaultScheduler.prototype.schedule = function (state, action) {
      var disposable = new SingleAssignmentDisposable(),
          id = scheduleMethod(scheduleAction(disposable, action, this, state));
      return new BinaryDisposable(disposable, new ClearDisposable(id));
    };

    DefaultScheduler.prototype._scheduleFuture = function (state, dueTime, action) {
      if (dueTime === 0) { return this.schedule(state, action); }
      var disposable = new SingleAssignmentDisposable(),
          id = localSetTimeout(scheduleAction(disposable, action, this, state), dueTime);
      return new BinaryDisposable(disposable, new LocalClearDisposable(id));
    };

    return DefaultScheduler;
  }(Scheduler));

  var defaultScheduler = Scheduler['default'] = Scheduler.async = new DefaultScheduler();

  var CatchScheduler = (function (__super__) {
    inherits(CatchScheduler, __super__);

    function CatchScheduler(scheduler, handler) {
      this._scheduler = scheduler;
      this._handler = handler;
      this._recursiveOriginal = null;
      this._recursiveWrapper = null;
      __super__.call(this);
    }

    CatchScheduler.prototype.schedule = function (state, action) {
      return this._scheduler.schedule(state, this._wrap(action));
    };

    CatchScheduler.prototype._scheduleFuture = function (state, dueTime, action) {
      return this._scheduler.schedule(state, dueTime, this._wrap(action));
    };

    CatchScheduler.prototype.now = function () { return this._scheduler.now(); };

    CatchScheduler.prototype._clone = function (scheduler) {
        return new CatchScheduler(scheduler, this._handler);
    };

    CatchScheduler.prototype._wrap = function (action) {
      var parent = this;
      return function (self, state) {
        var res = tryCatch(action)(parent._getRecursiveWrapper(self), state);
        if (res === errorObj) {
          if (!parent._handler(res.e)) { thrower(res.e); }
          return disposableEmpty;
        }
        return disposableFixup(res);
      };
    };

    CatchScheduler.prototype._getRecursiveWrapper = function (scheduler) {
      if (this._recursiveOriginal !== scheduler) {
        this._recursiveOriginal = scheduler;
        var wrapper = this._clone(scheduler);
        wrapper._recursiveOriginal = scheduler;
        wrapper._recursiveWrapper = wrapper;
        this._recursiveWrapper = wrapper;
      }
      return this._recursiveWrapper;
    };

    CatchScheduler.prototype.schedulePeriodic = function (state, period, action) {
      var self = this, failed = false, d = new SingleAssignmentDisposable();

      d.setDisposable(this._scheduler.schedulePeriodic(state, period, function (state1) {
        if (failed) { return null; }
        var res = tryCatch(action)(state1);
        if (res === errorObj) {
          failed = true;
          if (!self._handler(res.e)) { thrower(res.e); }
          d.dispose();
          return null;
        }
        return res;
      }));

      return d;
    };

    return CatchScheduler;
  }(Scheduler));

  function IndexedItem(id, value) {
    this.id = id;
    this.value = value;
  }

  IndexedItem.prototype.compareTo = function (other) {
    var c = this.value.compareTo(other.value);
    c === 0 && (c = this.id - other.id);
    return c;
  };

  var PriorityQueue = Rx.internals.PriorityQueue = function (capacity) {
    this.items = new Array(capacity);
    this.length = 0;
  };

  var priorityProto = PriorityQueue.prototype;
  priorityProto.isHigherPriority = function (left, right) {
    return this.items[left].compareTo(this.items[right]) < 0;
  };

  priorityProto.percolate = function (index) {
    if (index >= this.length || index < 0) { return; }
    var parent = index - 1 >> 1;
    if (parent < 0 || parent === index) { return; }
    if (this.isHigherPriority(index, parent)) {
      var temp = this.items[index];
      this.items[index] = this.items[parent];
      this.items[parent] = temp;
      this.percolate(parent);
    }
  };

  priorityProto.heapify = function (index) {
    +index || (index = 0);
    if (index >= this.length || index < 0) { return; }
    var left = 2 * index + 1,
        right = 2 * index + 2,
        first = index;
    if (left < this.length && this.isHigherPriority(left, first)) {
      first = left;
    }
    if (right < this.length && this.isHigherPriority(right, first)) {
      first = right;
    }
    if (first !== index) {
      var temp = this.items[index];
      this.items[index] = this.items[first];
      this.items[first] = temp;
      this.heapify(first);
    }
  };

  priorityProto.peek = function () { return this.items[0].value; };

  priorityProto.removeAt = function (index) {
    this.items[index] = this.items[--this.length];
    this.items[this.length] = undefined;
    this.heapify();
  };

  priorityProto.dequeue = function () {
    var result = this.peek();
    this.removeAt(0);
    return result;
  };

  priorityProto.enqueue = function (item) {
    var index = this.length++;
    this.items[index] = new IndexedItem(PriorityQueue.count++, item);
    this.percolate(index);
  };

  priorityProto.remove = function (item) {
    for (var i = 0; i < this.length; i++) {
      if (this.items[i].value === item) {
        this.removeAt(i);
        return true;
      }
    }
    return false;
  };
  PriorityQueue.count = 0;

  /**
   *  Represents a notification to an observer.
   */
  var Notification = Rx.Notification = (function () {
    function Notification() {

    }

    Notification.prototype._accept = function (onNext, onError, onCompleted) {
      throw new NotImplementedError();
    };

    Notification.prototype._acceptObserver = function (onNext, onError, onCompleted) {
      throw new NotImplementedError();
    };

    /**
     * Invokes the delegate corresponding to the notification or the observer's method corresponding to the notification and returns the produced result.
     * @param {Function | Observer} observerOrOnNext Function to invoke for an OnNext notification or Observer to invoke the notification on..
     * @param {Function} onError Function to invoke for an OnError notification.
     * @param {Function} onCompleted Function to invoke for an OnCompleted notification.
     * @returns {Any} Result produced by the observation.
     */
    Notification.prototype.accept = function (observerOrOnNext, onError, onCompleted) {
      return observerOrOnNext && typeof observerOrOnNext === 'object' ?
        this._acceptObserver(observerOrOnNext) :
        this._accept(observerOrOnNext, onError, onCompleted);
    };

    /**
     * Returns an observable sequence with a single notification.
     *
     * @memberOf Notifications
     * @param {Scheduler} [scheduler] Scheduler to send out the notification calls on.
     * @returns {Observable} The observable sequence that surfaces the behavior of the notification upon subscription.
     */
    Notification.prototype.toObservable = function (scheduler) {
      var self = this;
      isScheduler(scheduler) || (scheduler = immediateScheduler);
      return new AnonymousObservable(function (o) {
        return scheduler.schedule(self, function (_, notification) {
          notification._acceptObserver(o);
          notification.kind === 'N' && o.onCompleted();
        });
      });
    };

    return Notification;
  })();

  var OnNextNotification = (function (__super__) {
    inherits(OnNextNotification, __super__);
    function OnNextNotification(value) {
      this.value = value;
      this.kind = 'N';
    }

    OnNextNotification.prototype._accept = function (onNext) {
      return onNext(this.value);
    };

    OnNextNotification.prototype._acceptObserver = function (o) {
      return o.onNext(this.value);
    };

    OnNextNotification.prototype.toString = function () {
      return 'OnNext(' + this.value + ')';
    };

    return OnNextNotification;
  }(Notification));

  var OnErrorNotification = (function (__super__) {
    inherits(OnErrorNotification, __super__);
    function OnErrorNotification(error) {
      this.error = error;
      this.kind = 'E';
    }

    OnErrorNotification.prototype._accept = function (onNext, onError) {
      return onError(this.error);
    };

    OnErrorNotification.prototype._acceptObserver = function (o) {
      return o.onError(this.error);
    };

    OnErrorNotification.prototype.toString = function () {
      return 'OnError(' + this.error + ')';
    };

    return OnErrorNotification;
  }(Notification));

  var OnCompletedNotification = (function (__super__) {
    inherits(OnCompletedNotification, __super__);
    function OnCompletedNotification() {
      this.kind = 'C';
    }

    OnCompletedNotification.prototype._accept = function (onNext, onError, onCompleted) {
      return onCompleted();
    };

    OnCompletedNotification.prototype._acceptObserver = function (o) {
      return o.onCompleted();
    };

    OnCompletedNotification.prototype.toString = function () {
      return 'OnCompleted()';
    };

    return OnCompletedNotification;
  }(Notification));

  /**
   * Creates an object that represents an OnNext notification to an observer.
   * @param {Any} value The value contained in the notification.
   * @returns {Notification} The OnNext notification containing the value.
   */
  var notificationCreateOnNext = Notification.createOnNext = function (value) {
    return new OnNextNotification(value);
  };

  /**
   * Creates an object that represents an OnError notification to an observer.
   * @param {Any} error The exception contained in the notification.
   * @returns {Notification} The OnError notification containing the exception.
   */
  var notificationCreateOnError = Notification.createOnError = function (error) {
    return new OnErrorNotification(error);
  };

  /**
   * Creates an object that represents an OnCompleted notification to an observer.
   * @returns {Notification} The OnCompleted notification.
   */
  var notificationCreateOnCompleted = Notification.createOnCompleted = function () {
    return new OnCompletedNotification();
  };

  /**
   * Supports push-style iteration over an observable sequence.
   */
  var Observer = Rx.Observer = function () { };

  /**
   *  Creates a notification callback from an observer.
   * @returns The action that forwards its input notification to the underlying observer.
   */
  Observer.prototype.toNotifier = function () {
    var observer = this;
    return function (n) { return n.accept(observer); };
  };

  /**
   *  Hides the identity of an observer.
   * @returns An observer that hides the identity of the specified observer.
   */
  Observer.prototype.asObserver = function () {
    var self = this;
    return new AnonymousObserver(
      function (x) { self.onNext(x); },
      function (err) { self.onError(err); },
      function () { self.onCompleted(); });
  };

  /**
   *  Checks access to the observer for grammar violations. This includes checking for multiple OnError or OnCompleted calls, as well as reentrancy in any of the observer methods.
   *  If a violation is detected, an Error is thrown from the offending observer method call.
   * @returns An observer that checks callbacks invocations against the observer grammar and, if the checks pass, forwards those to the specified observer.
   */
  Observer.prototype.checked = function () { return new CheckedObserver(this); };

  /**
   *  Creates an observer from the specified OnNext, along with optional OnError, and OnCompleted actions.
   * @param {Function} [onNext] Observer's OnNext action implementation.
   * @param {Function} [onError] Observer's OnError action implementation.
   * @param {Function} [onCompleted] Observer's OnCompleted action implementation.
   * @returns {Observer} The observer object implemented using the given actions.
   */
  var observerCreate = Observer.create = function (onNext, onError, onCompleted) {
    onNext || (onNext = noop);
    onError || (onError = defaultError);
    onCompleted || (onCompleted = noop);
    return new AnonymousObserver(onNext, onError, onCompleted);
  };

  /**
   *  Creates an observer from a notification callback.
   * @param {Function} handler Action that handles a notification.
   * @returns The observer object that invokes the specified handler using a notification corresponding to each message it receives.
   */
  Observer.fromNotifier = function (handler, thisArg) {
    var cb = bindCallback(handler, thisArg, 1);
    return new AnonymousObserver(function (x) {
      return cb(notificationCreateOnNext(x));
    }, function (e) {
      return cb(notificationCreateOnError(e));
    }, function () {
      return cb(notificationCreateOnCompleted());
    });
  };

  /**
   * Schedules the invocation of observer methods on the given scheduler.
   * @param {Scheduler} scheduler Scheduler to schedule observer messages on.
   * @returns {Observer} Observer whose messages are scheduled on the given scheduler.
   */
  Observer.prototype.notifyOn = function (scheduler) {
    return new ObserveOnObserver(scheduler, this);
  };

  Observer.prototype.makeSafe = function(disposable) {
    return new AnonymousSafeObserver(this._onNext, this._onError, this._onCompleted, disposable);
  };

  /**
   * Abstract base class for implementations of the Observer class.
   * This base class enforces the grammar of observers where OnError and OnCompleted are terminal messages.
   */
  var AbstractObserver = Rx.internals.AbstractObserver = (function (__super__) {
    inherits(AbstractObserver, __super__);

    /**
     * Creates a new observer in a non-stopped state.
     */
    function AbstractObserver() {
      this.isStopped = false;
    }

    // Must be implemented by other observers
    AbstractObserver.prototype.next = notImplemented;
    AbstractObserver.prototype.error = notImplemented;
    AbstractObserver.prototype.completed = notImplemented;

    /**
     * Notifies the observer of a new element in the sequence.
     * @param {Any} value Next element in the sequence.
     */
    AbstractObserver.prototype.onNext = function (value) {
      !this.isStopped && this.next(value);
    };

    /**
     * Notifies the observer that an exception has occurred.
     * @param {Any} error The error that has occurred.
     */
    AbstractObserver.prototype.onError = function (error) {
      if (!this.isStopped) {
        this.isStopped = true;
        this.error(error);
      }
    };

    /**
     * Notifies the observer of the end of the sequence.
     */
    AbstractObserver.prototype.onCompleted = function () {
      if (!this.isStopped) {
        this.isStopped = true;
        this.completed();
      }
    };

    /**
     * Disposes the observer, causing it to transition to the stopped state.
     */
    AbstractObserver.prototype.dispose = function () { this.isStopped = true; };

    AbstractObserver.prototype.fail = function (e) {
      if (!this.isStopped) {
        this.isStopped = true;
        this.error(e);
        return true;
      }

      return false;
    };

    return AbstractObserver;
  }(Observer));

  /**
   * Class to create an Observer instance from delegate-based implementations of the on* methods.
   */
  var AnonymousObserver = Rx.AnonymousObserver = (function (__super__) {
    inherits(AnonymousObserver, __super__);

    /**
     * Creates an observer from the specified OnNext, OnError, and OnCompleted actions.
     * @param {Any} onNext Observer's OnNext action implementation.
     * @param {Any} onError Observer's OnError action implementation.
     * @param {Any} onCompleted Observer's OnCompleted action implementation.
     */
    function AnonymousObserver(onNext, onError, onCompleted) {
      __super__.call(this);
      this._onNext = onNext;
      this._onError = onError;
      this._onCompleted = onCompleted;
    }

    /**
     * Calls the onNext action.
     * @param {Any} value Next element in the sequence.
     */
    AnonymousObserver.prototype.next = function (value) {
      this._onNext(value);
    };

    /**
     * Calls the onError action.
     * @param {Any} error The error that has occurred.
     */
    AnonymousObserver.prototype.error = function (error) {
      this._onError(error);
    };

    /**
     *  Calls the onCompleted action.
     */
    AnonymousObserver.prototype.completed = function () {
      this._onCompleted();
    };

    return AnonymousObserver;
  }(AbstractObserver));

  var CheckedObserver = (function (__super__) {
    inherits(CheckedObserver, __super__);

    function CheckedObserver(observer) {
      __super__.call(this);
      this._observer = observer;
      this._state = 0; // 0 - idle, 1 - busy, 2 - done
    }

    var CheckedObserverPrototype = CheckedObserver.prototype;

    CheckedObserverPrototype.onNext = function (value) {
      this.checkAccess();
      var res = tryCatch(this._observer.onNext).call(this._observer, value);
      this._state = 0;
      res === errorObj && thrower(res.e);
    };

    CheckedObserverPrototype.onError = function (err) {
      this.checkAccess();
      var res = tryCatch(this._observer.onError).call(this._observer, err);
      this._state = 2;
      res === errorObj && thrower(res.e);
    };

    CheckedObserverPrototype.onCompleted = function () {
      this.checkAccess();
      var res = tryCatch(this._observer.onCompleted).call(this._observer);
      this._state = 2;
      res === errorObj && thrower(res.e);
    };

    CheckedObserverPrototype.checkAccess = function () {
      if (this._state === 1) { throw new Error('Re-entrancy detected'); }
      if (this._state === 2) { throw new Error('Observer completed'); }
      if (this._state === 0) { this._state = 1; }
    };

    return CheckedObserver;
  }(Observer));

  var ScheduledObserver = Rx.internals.ScheduledObserver = (function (__super__) {
    inherits(ScheduledObserver, __super__);

    function ScheduledObserver(scheduler, observer) {
      __super__.call(this);
      this.scheduler = scheduler;
      this.observer = observer;
      this.isAcquired = false;
      this.hasFaulted = false;
      this.queue = [];
      this.disposable = new SerialDisposable();
    }

    function enqueueNext(observer, x) { return function () { observer.onNext(x); }; }
    function enqueueError(observer, e) { return function () { observer.onError(e); }; }
    function enqueueCompleted(observer) { return function () { observer.onCompleted(); }; }

    ScheduledObserver.prototype.next = function (x) {
      this.queue.push(enqueueNext(this.observer, x));
    };

    ScheduledObserver.prototype.error = function (e) {
      this.queue.push(enqueueError(this.observer, e));
    };

    ScheduledObserver.prototype.completed = function () {
      this.queue.push(enqueueCompleted(this.observer));
    };


    function scheduleMethod(state, recurse) {
      var work;
      if (state.queue.length > 0) {
        work = state.queue.shift();
      } else {
        state.isAcquired = false;
        return;
      }
      var res = tryCatch(work)();
      if (res === errorObj) {
        state.queue = [];
        state.hasFaulted = true;
        return thrower(res.e);
      }
      recurse(state);
    }

    ScheduledObserver.prototype.ensureActive = function () {
      var isOwner = false;
      if (!this.hasFaulted && this.queue.length > 0) {
        isOwner = !this.isAcquired;
        this.isAcquired = true;
      }
      isOwner &&
        this.disposable.setDisposable(this.scheduler.scheduleRecursive(this, scheduleMethod));
    };

    ScheduledObserver.prototype.dispose = function () {
      __super__.prototype.dispose.call(this);
      this.disposable.dispose();
    };

    return ScheduledObserver;
  }(AbstractObserver));

  var ObserveOnObserver = (function (__super__) {
    inherits(ObserveOnObserver, __super__);

    function ObserveOnObserver(scheduler, observer, cancel) {
      __super__.call(this, scheduler, observer);
      this._cancel = cancel;
    }

    ObserveOnObserver.prototype.next = function (value) {
      __super__.prototype.next.call(this, value);
      this.ensureActive();
    };

    ObserveOnObserver.prototype.error = function (e) {
      __super__.prototype.error.call(this, e);
      this.ensureActive();
    };

    ObserveOnObserver.prototype.completed = function () {
      __super__.prototype.completed.call(this);
      this.ensureActive();
    };

    ObserveOnObserver.prototype.dispose = function () {
      __super__.prototype.dispose.call(this);
      this._cancel && this._cancel.dispose();
      this._cancel = null;
    };

    return ObserveOnObserver;
  })(ScheduledObserver);

  var observableProto;

  /**
   * Represents a push-style collection.
   */
  var Observable = Rx.Observable = (function () {

    function makeSubscribe(self, subscribe) {
      return function (o) {
        var oldOnError = o.onError;
        o.onError = function (e) {
          makeStackTraceLong(e, self);
          oldOnError.call(o, e);
        };

        return subscribe.call(self, o);
      };
    }

    function Observable() {
      if (Rx.config.longStackSupport && hasStacks) {
        var oldSubscribe = this._subscribe;
        var e = tryCatch(thrower)(new Error()).e;
        this.stack = e.stack.substring(e.stack.indexOf('\n') + 1);
        this._subscribe = makeSubscribe(this, oldSubscribe);
      }
    }

    observableProto = Observable.prototype;

    /**
    * Determines whether the given object is an Observable
    * @param {Any} An object to determine whether it is an Observable
    * @returns {Boolean} true if an Observable, else false.
    */
    Observable.isObservable = function (o) {
      return o && isFunction(o.subscribe);
    };

    /**
     *  Subscribes an o to the observable sequence.
     *  @param {Mixed} [oOrOnNext] The object that is to receive notifications or an action to invoke for each element in the observable sequence.
     *  @param {Function} [onError] Action to invoke upon exceptional termination of the observable sequence.
     *  @param {Function} [onCompleted] Action to invoke upon graceful termination of the observable sequence.
     *  @returns {Diposable} A disposable handling the subscriptions and unsubscriptions.
     */
    observableProto.subscribe = observableProto.forEach = function (oOrOnNext, onError, onCompleted) {
      return this._subscribe(typeof oOrOnNext === 'object' ?
        oOrOnNext :
        observerCreate(oOrOnNext, onError, onCompleted));
    };

    /**
     * Subscribes to the next value in the sequence with an optional "this" argument.
     * @param {Function} onNext The function to invoke on each element in the observable sequence.
     * @param {Any} [thisArg] Object to use as this when executing callback.
     * @returns {Disposable} A disposable handling the subscriptions and unsubscriptions.
     */
    observableProto.subscribeOnNext = function (onNext, thisArg) {
      return this._subscribe(observerCreate(typeof thisArg !== 'undefined' ? function(x) { onNext.call(thisArg, x); } : onNext));
    };

    /**
     * Subscribes to an exceptional condition in the sequence with an optional "this" argument.
     * @param {Function} onError The function to invoke upon exceptional termination of the observable sequence.
     * @param {Any} [thisArg] Object to use as this when executing callback.
     * @returns {Disposable} A disposable handling the subscriptions and unsubscriptions.
     */
    observableProto.subscribeOnError = function (onError, thisArg) {
      return this._subscribe(observerCreate(null, typeof thisArg !== 'undefined' ? function(e) { onError.call(thisArg, e); } : onError));
    };

    /**
     * Subscribes to the next value in the sequence with an optional "this" argument.
     * @param {Function} onCompleted The function to invoke upon graceful termination of the observable sequence.
     * @param {Any} [thisArg] Object to use as this when executing callback.
     * @returns {Disposable} A disposable handling the subscriptions and unsubscriptions.
     */
    observableProto.subscribeOnCompleted = function (onCompleted, thisArg) {
      return this._subscribe(observerCreate(null, null, typeof thisArg !== 'undefined' ? function() { onCompleted.call(thisArg); } : onCompleted));
    };

    return Observable;
  })();

  var ObservableBase = Rx.ObservableBase = (function (__super__) {
    inherits(ObservableBase, __super__);

    function fixSubscriber(subscriber) {
      return subscriber && isFunction(subscriber.dispose) ? subscriber :
        isFunction(subscriber) ? disposableCreate(subscriber) : disposableEmpty;
    }

    function setDisposable(s, state) {
      var ado = state[0], self = state[1];
      var sub = tryCatch(self.subscribeCore).call(self, ado);
      if (sub === errorObj && !ado.fail(errorObj.e)) { thrower(errorObj.e); }
      ado.setDisposable(fixSubscriber(sub));
    }

    function ObservableBase() {
      __super__.call(this);
    }

    ObservableBase.prototype._subscribe = function (o) {
      var ado = new AutoDetachObserver(o), state = [ado, this];

      if (currentThreadScheduler.scheduleRequired()) {
        currentThreadScheduler.schedule(state, setDisposable);
      } else {
        setDisposable(null, state);
      }
      return ado;
    };

    ObservableBase.prototype.subscribeCore = notImplemented;

    return ObservableBase;
  }(Observable));

var FlatMapObservable = Rx.FlatMapObservable = (function(__super__) {

    inherits(FlatMapObservable, __super__);

    function FlatMapObservable(source, selector, resultSelector, thisArg) {
      this.resultSelector = isFunction(resultSelector) ? resultSelector : null;
      this.selector = bindCallback(isFunction(selector) ? selector : function() { return selector; }, thisArg, 3);
      this.source = source;
      __super__.call(this);
    }

    FlatMapObservable.prototype.subscribeCore = function(o) {
      return this.source.subscribe(new InnerObserver(o, this.selector, this.resultSelector, this));
    };

    inherits(InnerObserver, AbstractObserver);
    function InnerObserver(observer, selector, resultSelector, source) {
      this.i = 0;
      this.selector = selector;
      this.resultSelector = resultSelector;
      this.source = source;
      this.o = observer;
      AbstractObserver.call(this);
    }

    InnerObserver.prototype._wrapResult = function(result, x, i) {
      return this.resultSelector ?
        result.map(function(y, i2) { return this.resultSelector(x, y, i, i2); }, this) :
        result;
    };

    InnerObserver.prototype.next = function(x) {
      var i = this.i++;
      var result = tryCatch(this.selector)(x, i, this.source);
      if (result === errorObj) { return this.o.onError(result.e); }

      isPromise(result) && (result = observableFromPromise(result));
      (isArrayLike(result) || isIterable(result)) && (result = Observable.from(result));
      this.o.onNext(this._wrapResult(result, x, i));
    };

    InnerObserver.prototype.error = function(e) { this.o.onError(e); };

    InnerObserver.prototype.completed = function() { this.o.onCompleted(); };

    return FlatMapObservable;

}(ObservableBase));

  var Enumerable = Rx.internals.Enumerable = function () { };

  function IsDisposedDisposable(state) {
    this._s = state;
    this.isDisposed = false;
  }

  IsDisposedDisposable.prototype.dispose = function () {
    if (!this.isDisposed) {
      this.isDisposed = true;
      this._s.isDisposed = true;
    }
  };

  var ConcatEnumerableObservable = (function(__super__) {
    inherits(ConcatEnumerableObservable, __super__);
    function ConcatEnumerableObservable(sources) {
      this.sources = sources;
      __super__.call(this);
    }

    function scheduleMethod(state, recurse) {
      if (state.isDisposed) { return; }
      var currentItem = tryCatch(state.e.next).call(state.e);
      if (currentItem === errorObj) { return state.o.onError(currentItem.e); }
      if (currentItem.done) { return state.o.onCompleted(); }

      // Check if promise
      var currentValue = currentItem.value;
      isPromise(currentValue) && (currentValue = observableFromPromise(currentValue));

      var d = new SingleAssignmentDisposable();
      state.subscription.setDisposable(d);
      d.setDisposable(currentValue.subscribe(new InnerObserver(state, recurse)));
    }

    ConcatEnumerableObservable.prototype.subscribeCore = function (o) {
      var subscription = new SerialDisposable();
      var state = {
        isDisposed: false,
        o: o,
        subscription: subscription,
        e: this.sources[$iterator$]()
      };

      var cancelable = currentThreadScheduler.scheduleRecursive(state, scheduleMethod);
      return new NAryDisposable([subscription, cancelable, new IsDisposedDisposable(state)]);
    };

    function InnerObserver(state, recurse) {
      this._state = state;
      this._recurse = recurse;
      AbstractObserver.call(this);
    }

    inherits(InnerObserver, AbstractObserver);

    InnerObserver.prototype.next = function (x) { this._state.o.onNext(x); };
    InnerObserver.prototype.error = function (e) { this._state.o.onError(e); };
    InnerObserver.prototype.completed = function () { this._recurse(this._state); };

    return ConcatEnumerableObservable;
  }(ObservableBase));

  Enumerable.prototype.concat = function () {
    return new ConcatEnumerableObservable(this);
  };

  var CatchErrorObservable = (function(__super__) {
    function CatchErrorObservable(sources) {
      this.sources = sources;
      __super__.call(this);
    }

    inherits(CatchErrorObservable, __super__);

    function scheduleMethod(state, recurse) {
      if (state.isDisposed) { return; }
      var currentItem = tryCatch(state.e.next).call(state.e);
      if (currentItem === errorObj) { return state.o.onError(currentItem.e); }
      if (currentItem.done) { return state.lastError !== null ? state.o.onError(state.lastError) : state.o.onCompleted(); }

      var currentValue = currentItem.value;
      isPromise(currentValue) && (currentValue = observableFromPromise(currentValue));

      var d = new SingleAssignmentDisposable();
      state.subscription.setDisposable(d);
      d.setDisposable(currentValue.subscribe(new InnerObserver(state, recurse)));
    }

    CatchErrorObservable.prototype.subscribeCore = function (o) {
      var subscription = new SerialDisposable();
      var state = {
        isDisposed: false,
        e: this.sources[$iterator$](),
        subscription: subscription,
        lastError: null,
        o: o
      };

      var cancelable = currentThreadScheduler.scheduleRecursive(state, scheduleMethod);
      return new NAryDisposable([subscription, cancelable, new IsDisposedDisposable(state)]);
    };

    function InnerObserver(state, recurse) {
      this._state = state;
      this._recurse = recurse;
      AbstractObserver.call(this);
    }

    inherits(InnerObserver, AbstractObserver);

    InnerObserver.prototype.next = function (x) { this._state.o.onNext(x); };
    InnerObserver.prototype.error = function (e) { this._state.lastError = e; this._recurse(this._state); };
    InnerObserver.prototype.completed = function () { this._state.o.onCompleted(); };

    return CatchErrorObservable;
  }(ObservableBase));

  Enumerable.prototype.catchError = function () {
    return new CatchErrorObservable(this);
  };

  Enumerable.prototype.catchErrorWhen = function (notificationHandler) {
    var sources = this;
    return new AnonymousObservable(function (o) {
      var exceptions = new Subject(),
        notifier = new Subject(),
        handled = notificationHandler(exceptions),
        notificationDisposable = handled.subscribe(notifier);

      var e = sources[$iterator$]();

      var state = { isDisposed: false },
        lastError,
        subscription = new SerialDisposable();
      var cancelable = currentThreadScheduler.scheduleRecursive(null, function (_, self) {
        if (state.isDisposed) { return; }
        var currentItem = tryCatch(e.next).call(e);
        if (currentItem === errorObj) { return o.onError(currentItem.e); }

        if (currentItem.done) {
          if (lastError) {
            o.onError(lastError);
          } else {
            o.onCompleted();
          }
          return;
        }

        // Check if promise
        var currentValue = currentItem.value;
        isPromise(currentValue) && (currentValue = observableFromPromise(currentValue));

        var outer = new SingleAssignmentDisposable();
        var inner = new SingleAssignmentDisposable();
        subscription.setDisposable(new BinaryDisposable(inner, outer));
        outer.setDisposable(currentValue.subscribe(
          function(x) { o.onNext(x); },
          function (exn) {
            inner.setDisposable(notifier.subscribe(self, function(ex) {
              o.onError(ex);
            }, function() {
              o.onCompleted();
            }));

            exceptions.onNext(exn);
          },
          function() { o.onCompleted(); }));
      });

      return new NAryDisposable([notificationDisposable, subscription, cancelable, new IsDisposedDisposable(state)]);
    });
  };

  var RepeatEnumerable = (function (__super__) {
    inherits(RepeatEnumerable, __super__);
    function RepeatEnumerable(v, c) {
      this.v = v;
      this.c = c == null ? -1 : c;
    }

    RepeatEnumerable.prototype[$iterator$] = function () {
      return new RepeatEnumerator(this);
    };

    function RepeatEnumerator(p) {
      this.v = p.v;
      this.l = p.c;
    }

    RepeatEnumerator.prototype.next = function () {
      if (this.l === 0) { return doneEnumerator; }
      if (this.l > 0) { this.l--; }
      return { done: false, value: this.v };
    };

    return RepeatEnumerable;
  }(Enumerable));

  var enumerableRepeat = Enumerable.repeat = function (value, repeatCount) {
    return new RepeatEnumerable(value, repeatCount);
  };

  var OfEnumerable = (function(__super__) {
    inherits(OfEnumerable, __super__);
    function OfEnumerable(s, fn, thisArg) {
      this.s = s;
      this.fn = fn ? bindCallback(fn, thisArg, 3) : null;
    }
    OfEnumerable.prototype[$iterator$] = function () {
      return new OfEnumerator(this);
    };

    function OfEnumerator(p) {
      this.i = -1;
      this.s = p.s;
      this.l = this.s.length;
      this.fn = p.fn;
    }

    OfEnumerator.prototype.next = function () {
     return ++this.i < this.l ?
       { done: false, value: !this.fn ? this.s[this.i] : this.fn(this.s[this.i], this.i, this.s) } :
       doneEnumerator;
    };

    return OfEnumerable;
  }(Enumerable));

  var enumerableOf = Enumerable.of = function (source, selector, thisArg) {
    return new OfEnumerable(source, selector, thisArg);
  };

var ObserveOnObservable = (function (__super__) {
  inherits(ObserveOnObservable, __super__);
  function ObserveOnObservable(source, s) {
    this.source = source;
    this._s = s;
    __super__.call(this);
  }

  ObserveOnObservable.prototype.subscribeCore = function (o) {
    return this.source.subscribe(new ObserveOnObserver(this._s, o));
  };

  return ObserveOnObservable;
}(ObservableBase));

   /**
   *  Wraps the source sequence in order to run its observer callbacks on the specified scheduler.
   *
   *  This only invokes observer callbacks on a scheduler. In case the subscription and/or unsubscription actions have side-effects
   *  that require to be run on a scheduler, use subscribeOn.
   *
   *  @param {Scheduler} scheduler Scheduler to notify observers on.
   *  @returns {Observable} The source sequence whose observations happen on the specified scheduler.
   */
  observableProto.observeOn = function (scheduler) {
    return new ObserveOnObservable(this, scheduler);
  };

  var SubscribeOnObservable = (function (__super__) {
    inherits(SubscribeOnObservable, __super__);
    function SubscribeOnObservable(source, s) {
      this.source = source;
      this._s = s;
      __super__.call(this);
    }

    function scheduleMethod(scheduler, state) {
      var source = state[0], d = state[1], o = state[2];
      d.setDisposable(new ScheduledDisposable(scheduler, source.subscribe(o)));
    }

    SubscribeOnObservable.prototype.subscribeCore = function (o) {
      var m = new SingleAssignmentDisposable(), d = new SerialDisposable();
      d.setDisposable(m);
      m.setDisposable(this._s.schedule([this.source, d, o], scheduleMethod));
      return d;
    };

    return SubscribeOnObservable;
  }(ObservableBase));

   /**
   *  Wraps the source sequence in order to run its subscription and unsubscription logic on the specified scheduler. This operation is not commonly used;
   *  see the remarks section for more information on the distinction between subscribeOn and observeOn.

   *  This only performs the side-effects of subscription and unsubscription on the specified scheduler. In order to invoke observer
   *  callbacks on a scheduler, use observeOn.

   *  @param {Scheduler} scheduler Scheduler to perform subscription and unsubscription actions on.
   *  @returns {Observable} The source sequence whose subscriptions and unsubscriptions happen on the specified scheduler.
   */
  observableProto.subscribeOn = function (scheduler) {
    return new SubscribeOnObservable(this, scheduler);
  };

  var FromPromiseObservable = (function(__super__) {
    inherits(FromPromiseObservable, __super__);
    function FromPromiseObservable(p, s) {
      this._p = p;
      this._s = s;
      __super__.call(this);
    }

    function scheduleNext(s, state) {
      var o = state[0], data = state[1];
      o.onNext(data);
      o.onCompleted();
    }

    function scheduleError(s, state) {
      var o = state[0], err = state[1];
      o.onError(err);
    }

    FromPromiseObservable.prototype.subscribeCore = function(o) {
      var sad = new SingleAssignmentDisposable(), self = this;

      this._p
        .then(function (data) {
          sad.setDisposable(self._s.schedule([o, data], scheduleNext));
        }, function (err) {
          sad.setDisposable(self._s.schedule([o, err], scheduleError));
        });

      return sad;
    };

    return FromPromiseObservable;
  }(ObservableBase));

  /**
  * Converts a Promise to an Observable sequence
  * @param {Promise} An ES6 Compliant promise.
  * @returns {Observable} An Observable sequence which wraps the existing promise success and failure.
  */
  var observableFromPromise = Observable.fromPromise = function (promise, scheduler) {
    scheduler || (scheduler = defaultScheduler);
    return new FromPromiseObservable(promise, scheduler);
  };

  /*
   * Converts an existing observable sequence to an ES6 Compatible Promise
   * @example
   * var promise = Rx.Observable.return(42).toPromise(RSVP.Promise);
   *
   * // With config
   * Rx.config.Promise = RSVP.Promise;
   * var promise = Rx.Observable.return(42).toPromise();
   * @param {Function} [promiseCtor] The constructor of the promise. If not provided, it looks for it in Rx.config.Promise.
   * @returns {Promise} An ES6 compatible promise with the last value from the observable sequence.
   */
  observableProto.toPromise = function (promiseCtor) {
    promiseCtor || (promiseCtor = Rx.config.Promise);
    if (!promiseCtor) { throw new NotSupportedError('Promise type not provided nor in Rx.config.Promise'); }
    var source = this;
    return new promiseCtor(function (resolve, reject) {
      // No cancellation can be done
      var value;
      source.subscribe(function (v) {
        value = v;
      }, reject, function () {
        resolve(value);
      });
    });
  };

  var ToArrayObservable = (function(__super__) {
    inherits(ToArrayObservable, __super__);
    function ToArrayObservable(source) {
      this.source = source;
      __super__.call(this);
    }

    ToArrayObservable.prototype.subscribeCore = function(o) {
      return this.source.subscribe(new InnerObserver(o));
    };

    inherits(InnerObserver, AbstractObserver);
    function InnerObserver(o) {
      this.o = o;
      this.a = [];
      AbstractObserver.call(this);
    }
    
    InnerObserver.prototype.next = function (x) { this.a.push(x); };
    InnerObserver.prototype.error = function (e) { this.o.onError(e);  };
    InnerObserver.prototype.completed = function () { this.o.onNext(this.a); this.o.onCompleted(); };

    return ToArrayObservable;
  }(ObservableBase));

  /**
  * Creates an array from an observable sequence.
  * @returns {Observable} An observable sequence containing a single element with a list containing all the elements of the source sequence.
  */
  observableProto.toArray = function () {
    return new ToArrayObservable(this);
  };

  /**
   *  Creates an observable sequence from a specified subscribe method implementation.
   * @example
   *  var res = Rx.Observable.create(function (observer) { return function () { } );
   *  var res = Rx.Observable.create(function (observer) { return Rx.Disposable.empty; } );
   *  var res = Rx.Observable.create(function (observer) { } );
   * @param {Function} subscribe Implementation of the resulting observable sequence's subscribe method, returning a function that will be wrapped in a Disposable.
   * @returns {Observable} The observable sequence with the specified implementation for the Subscribe method.
   */
  Observable.create = function (subscribe, parent) {
    return new AnonymousObservable(subscribe, parent);
  };

  var Defer = (function(__super__) {
    inherits(Defer, __super__);
    function Defer(factory) {
      this._f = factory;
      __super__.call(this);
    }

    Defer.prototype.subscribeCore = function (o) {
      var result = tryCatch(this._f)();
      if (result === errorObj) { return observableThrow(result.e).subscribe(o);}
      isPromise(result) && (result = observableFromPromise(result));
      return result.subscribe(o);
    };

    return Defer;
  }(ObservableBase));

  /**
   *  Returns an observable sequence that invokes the specified factory function whenever a new observer subscribes.
   *
   * @example
   *  var res = Rx.Observable.defer(function () { return Rx.Observable.fromArray([1,2,3]); });
   * @param {Function} observableFactory Observable factory function to invoke for each observer that subscribes to the resulting sequence or Promise.
   * @returns {Observable} An observable sequence whose observers trigger an invocation of the given observable factory function.
   */
  var observableDefer = Observable.defer = function (observableFactory) {
    return new Defer(observableFactory);
  };

  var EmptyObservable = (function(__super__) {
    inherits(EmptyObservable, __super__);
    function EmptyObservable(scheduler) {
      this.scheduler = scheduler;
      __super__.call(this);
    }

    EmptyObservable.prototype.subscribeCore = function (observer) {
      var sink = new EmptySink(observer, this.scheduler);
      return sink.run();
    };

    function EmptySink(observer, scheduler) {
      this.observer = observer;
      this.scheduler = scheduler;
    }

    function scheduleItem(s, state) {
      state.onCompleted();
      return disposableEmpty;
    }

    EmptySink.prototype.run = function () {
      var state = this.observer;
      return this.scheduler === immediateScheduler ?
        scheduleItem(null, state) :
        this.scheduler.schedule(state, scheduleItem);
    };

    return EmptyObservable;
  }(ObservableBase));

  var EMPTY_OBSERVABLE = new EmptyObservable(immediateScheduler);

  /**
   *  Returns an empty observable sequence, using the specified scheduler to send out the single OnCompleted message.
   *
   * @example
   *  var res = Rx.Observable.empty();
   *  var res = Rx.Observable.empty(Rx.Scheduler.timeout);
   * @param {Scheduler} [scheduler] Scheduler to send the termination call on.
   * @returns {Observable} An observable sequence with no elements.
   */
  var observableEmpty = Observable.empty = function (scheduler) {
    isScheduler(scheduler) || (scheduler = immediateScheduler);
    return scheduler === immediateScheduler ? EMPTY_OBSERVABLE : new EmptyObservable(scheduler);
  };

  var FromObservable = (function(__super__) {
    inherits(FromObservable, __super__);
    function FromObservable(iterable, fn, scheduler) {
      this._iterable = iterable;
      this._fn = fn;
      this._scheduler = scheduler;
      __super__.call(this);
    }

    function createScheduleMethod(o, it, fn) {
      return function loopRecursive(i, recurse) {
        var next = tryCatch(it.next).call(it);
        if (next === errorObj) { return o.onError(next.e); }
        if (next.done) { return o.onCompleted(); }

        var result = next.value;

        if (isFunction(fn)) {
          result = tryCatch(fn)(result, i);
          if (result === errorObj) { return o.onError(result.e); }
        }

        o.onNext(result);
        recurse(i + 1);
      };
    }

    FromObservable.prototype.subscribeCore = function (o) {
      var list = Object(this._iterable),
          it = getIterable(list);

      return this._scheduler.scheduleRecursive(0, createScheduleMethod(o, it, this._fn));
    };

    return FromObservable;
  }(ObservableBase));

  var maxSafeInteger = Math.pow(2, 53) - 1;

  function StringIterable(s) {
    this._s = s;
  }

  StringIterable.prototype[$iterator$] = function () {
    return new StringIterator(this._s);
  };

  function StringIterator(s) {
    this._s = s;
    this._l = s.length;
    this._i = 0;
  }

  StringIterator.prototype[$iterator$] = function () {
    return this;
  };

  StringIterator.prototype.next = function () {
    return this._i < this._l ? { done: false, value: this._s.charAt(this._i++) } : doneEnumerator;
  };

  function ArrayIterable(a) {
    this._a = a;
  }

  ArrayIterable.prototype[$iterator$] = function () {
    return new ArrayIterator(this._a);
  };

  function ArrayIterator(a) {
    this._a = a;
    this._l = toLength(a);
    this._i = 0;
  }

  ArrayIterator.prototype[$iterator$] = function () {
    return this;
  };

  ArrayIterator.prototype.next = function () {
    return this._i < this._l ? { done: false, value: this._a[this._i++] } : doneEnumerator;
  };

  function numberIsFinite(value) {
    return typeof value === 'number' && root.isFinite(value);
  }

  function isNan(n) {
    return n !== n;
  }

  function getIterable(o) {
    var i = o[$iterator$], it;
    if (!i && typeof o === 'string') {
      it = new StringIterable(o);
      return it[$iterator$]();
    }
    if (!i && o.length !== undefined) {
      it = new ArrayIterable(o);
      return it[$iterator$]();
    }
    if (!i) { throw new TypeError('Object is not iterable'); }
    return o[$iterator$]();
  }

  function sign(value) {
    var number = +value;
    if (number === 0) { return number; }
    if (isNaN(number)) { return number; }
    return number < 0 ? -1 : 1;
  }

  function toLength(o) {
    var len = +o.length;
    if (isNaN(len)) { return 0; }
    if (len === 0 || !numberIsFinite(len)) { return len; }
    len = sign(len) * Math.floor(Math.abs(len));
    if (len <= 0) { return 0; }
    if (len > maxSafeInteger) { return maxSafeInteger; }
    return len;
  }

  /**
  * This method creates a new Observable sequence from an array-like or iterable object.
  * @param {Any} arrayLike An array-like or iterable object to convert to an Observable sequence.
  * @param {Function} [mapFn] Map function to call on every element of the array.
  * @param {Any} [thisArg] The context to use calling the mapFn if provided.
  * @param {Scheduler} [scheduler] Optional scheduler to use for scheduling.  If not provided, defaults to Scheduler.currentThread.
  */
  var observableFrom = Observable.from = function (iterable, mapFn, thisArg, scheduler) {
    if (iterable == null) {
      throw new Error('iterable cannot be null.')
    }
    if (mapFn && !isFunction(mapFn)) {
      throw new Error('mapFn when provided must be a function');
    }
    if (mapFn) {
      var mapper = bindCallback(mapFn, thisArg, 2);
    }
    isScheduler(scheduler) || (scheduler = currentThreadScheduler);
    return new FromObservable(iterable, mapper, scheduler);
  }

  var FromArrayObservable = (function(__super__) {
    inherits(FromArrayObservable, __super__);
    function FromArrayObservable(args, scheduler) {
      this._args = args;
      this._scheduler = scheduler;
      __super__.call(this);
    }

    function scheduleMethod(o, args) {
      var len = args.length;
      return function loopRecursive (i, recurse) {
        if (i < len) {
          o.onNext(args[i]);
          recurse(i + 1);
        } else {
          o.onCompleted();
        }
      };
    }

    FromArrayObservable.prototype.subscribeCore = function (o) {
      return this._scheduler.scheduleRecursive(0, scheduleMethod(o, this._args));
    };

    return FromArrayObservable;
  }(ObservableBase));

  /**
  *  Converts an array to an observable sequence, using an optional scheduler to enumerate the array.
  * @deprecated use Observable.from or Observable.of
  * @param {Scheduler} [scheduler] Scheduler to run the enumeration of the input sequence on.
  * @returns {Observable} The observable sequence whose elements are pulled from the given enumerable sequence.
  */
  var observableFromArray = Observable.fromArray = function (array, scheduler) {
    isScheduler(scheduler) || (scheduler = currentThreadScheduler);
    return new FromArrayObservable(array, scheduler)
  };

  var GenerateObservable = (function (__super__) {
    inherits(GenerateObservable, __super__);
    function GenerateObservable(state, cndFn, itrFn, resFn, s) {
      this._state = state;
      this._cndFn = cndFn;
      this._itrFn = itrFn;
      this._resFn = resFn;
      this._s = s;
      this._first = true;
      __super__.call(this);
    }

    function scheduleRecursive(self, recurse) {
      if (self._first) {
        self._first = false;
      } else {
        self._state = tryCatch(self._itrFn)(self._state);
        if (self._state === errorObj) { return self._o.onError(self._state.e); }
      }
      var hasResult = tryCatch(self._cndFn)(self._state);
      if (hasResult === errorObj) { return self._o.onError(hasResult.e); }
      if (hasResult) {
        var result = tryCatch(self._resFn)(self._state);
        if (result === errorObj) { return self._o.onError(result.e); }
        self._o.onNext(result);
        recurse(self);
      } else {
        self._o.onCompleted();
      }
    }

    GenerateObservable.prototype.subscribeCore = function (o) {
      this._o = o;
      return this._s.scheduleRecursive(this, scheduleRecursive);
    };

    return GenerateObservable;
  }(ObservableBase));

  /**
   *  Generates an observable sequence by running a state-driven loop producing the sequence's elements, using the specified scheduler to send out observer messages.
   *
   * @example
   *  var res = Rx.Observable.generate(0, function (x) { return x < 10; }, function (x) { return x + 1; }, function (x) { return x; });
   *  var res = Rx.Observable.generate(0, function (x) { return x < 10; }, function (x) { return x + 1; }, function (x) { return x; }, Rx.Scheduler.timeout);
   * @param {Mixed} initialState Initial state.
   * @param {Function} condition Condition to terminate generation (upon returning false).
   * @param {Function} iterate Iteration step function.
   * @param {Function} resultSelector Selector function for results produced in the sequence.
   * @param {Scheduler} [scheduler] Scheduler on which to run the generator loop. If not provided, defaults to Scheduler.currentThread.
   * @returns {Observable} The generated sequence.
   */
  Observable.generate = function (initialState, condition, iterate, resultSelector, scheduler) {
    isScheduler(scheduler) || (scheduler = currentThreadScheduler);
    return new GenerateObservable(initialState, condition, iterate, resultSelector, scheduler);
  };

  var NeverObservable = (function(__super__) {
    inherits(NeverObservable, __super__);
    function NeverObservable() {
      __super__.call(this);
    }

    NeverObservable.prototype.subscribeCore = function (observer) {
      return disposableEmpty;
    };

    return NeverObservable;
  }(ObservableBase));

  var NEVER_OBSERVABLE = new NeverObservable();

  /**
   * Returns a non-terminating observable sequence, which can be used to denote an infinite duration (e.g. when using reactive joins).
   * @returns {Observable} An observable sequence whose observers will never get called.
   */
  var observableNever = Observable.never = function () {
    return NEVER_OBSERVABLE;
  };

  function observableOf (scheduler, array) {
    isScheduler(scheduler) || (scheduler = currentThreadScheduler);
    return new FromArrayObservable(array, scheduler);
  }

  /**
  *  This method creates a new Observable instance with a variable number of arguments, regardless of number or type of the arguments.
  * @returns {Observable} The observable sequence whose elements are pulled from the given arguments.
  */
  Observable.of = function () {
    var len = arguments.length, args = new Array(len);
    for(var i = 0; i < len; i++) { args[i] = arguments[i]; }
    return new FromArrayObservable(args, currentThreadScheduler);
  };

  /**
  *  This method creates a new Observable instance with a variable number of arguments, regardless of number or type of the arguments.
  * @param {Scheduler} scheduler A scheduler to use for scheduling the arguments.
  * @returns {Observable} The observable sequence whose elements are pulled from the given arguments.
  */
  Observable.ofWithScheduler = function (scheduler) {
    var len = arguments.length, args = new Array(len - 1);
    for(var i = 1; i < len; i++) { args[i - 1] = arguments[i]; }
    return new FromArrayObservable(args, scheduler);
  };

  var PairsObservable = (function(__super__) {
    inherits(PairsObservable, __super__);
    function PairsObservable(o, scheduler) {
      this._o = o;
      this._keys = Object.keys(o);
      this._scheduler = scheduler;
      __super__.call(this);
    }

    function scheduleMethod(o, obj, keys) {
      return function loopRecursive(i, recurse) {
        if (i < keys.length) {
          var key = keys[i];
          o.onNext([key, obj[key]]);
          recurse(i + 1);
        } else {
          o.onCompleted();
        }
      };
    }

    PairsObservable.prototype.subscribeCore = function (o) {
      return this._scheduler.scheduleRecursive(0, scheduleMethod(o, this._o, this._keys));
    };

    return PairsObservable;
  }(ObservableBase));

  /**
   * Convert an object into an observable sequence of [key, value] pairs.
   * @param {Object} obj The object to inspect.
   * @param {Scheduler} [scheduler] Scheduler to run the enumeration of the input sequence on.
   * @returns {Observable} An observable sequence of [key, value] pairs from the object.
   */
  Observable.pairs = function (obj, scheduler) {
    scheduler || (scheduler = currentThreadScheduler);
    return new PairsObservable(obj, scheduler);
  };

    var RangeObservable = (function(__super__) {
    inherits(RangeObservable, __super__);
    function RangeObservable(start, count, scheduler) {
      this.start = start;
      this.rangeCount = count;
      this.scheduler = scheduler;
      __super__.call(this);
    }

    function loopRecursive(start, count, o) {
      return function loop (i, recurse) {
        if (i < count) {
          o.onNext(start + i);
          recurse(i + 1);
        } else {
          o.onCompleted();
        }
      };
    }

    RangeObservable.prototype.subscribeCore = function (o) {
      return this.scheduler.scheduleRecursive(
        0,
        loopRecursive(this.start, this.rangeCount, o)
      );
    };

    return RangeObservable;
  }(ObservableBase));

  /**
  *  Generates an observable sequence of integral numbers within a specified range, using the specified scheduler to send out observer messages.
  * @param {Number} start The value of the first integer in the sequence.
  * @param {Number} count The number of sequential integers to generate.
  * @param {Scheduler} [scheduler] Scheduler to run the generator loop on. If not specified, defaults to Scheduler.currentThread.
  * @returns {Observable} An observable sequence that contains a range of sequential integral numbers.
  */
  Observable.range = function (start, count, scheduler) {
    isScheduler(scheduler) || (scheduler = currentThreadScheduler);
    return new RangeObservable(start, count, scheduler);
  };

  var RepeatObservable = (function(__super__) {
    inherits(RepeatObservable, __super__);
    function RepeatObservable(value, repeatCount, scheduler) {
      this.value = value;
      this.repeatCount = repeatCount == null ? -1 : repeatCount;
      this.scheduler = scheduler;
      __super__.call(this);
    }

    RepeatObservable.prototype.subscribeCore = function (observer) {
      var sink = new RepeatSink(observer, this);
      return sink.run();
    };

    return RepeatObservable;
  }(ObservableBase));

  function RepeatSink(observer, parent) {
    this.observer = observer;
    this.parent = parent;
  }

  RepeatSink.prototype.run = function () {
    var observer = this.observer, value = this.parent.value;
    function loopRecursive(i, recurse) {
      if (i === -1 || i > 0) {
        observer.onNext(value);
        i > 0 && i--;
      }
      if (i === 0) { return observer.onCompleted(); }
      recurse(i);
    }

    return this.parent.scheduler.scheduleRecursive(this.parent.repeatCount, loopRecursive);
  };

  /**
   *  Generates an observable sequence that repeats the given element the specified number of times, using the specified scheduler to send out observer messages.
   * @param {Mixed} value Element to repeat.
   * @param {Number} repeatCount [Optiona] Number of times to repeat the element. If not specified, repeats indefinitely.
   * @param {Scheduler} scheduler Scheduler to run the producer loop on. If not specified, defaults to Scheduler.immediate.
   * @returns {Observable} An observable sequence that repeats the given element the specified number of times.
   */
  Observable.repeat = function (value, repeatCount, scheduler) {
    isScheduler(scheduler) || (scheduler = currentThreadScheduler);
    return new RepeatObservable(value, repeatCount, scheduler);
  };

  var JustObservable = (function(__super__) {
    inherits(JustObservable, __super__);
    function JustObservable(value, scheduler) {
      this._value = value;
      this._scheduler = scheduler;
      __super__.call(this);
    }

    JustObservable.prototype.subscribeCore = function (o) {
      var state = [this._value, o];
      return this._scheduler === immediateScheduler ?
        scheduleItem(null, state) :
        this._scheduler.schedule(state, scheduleItem);
    };

    function scheduleItem(s, state) {
      var value = state[0], observer = state[1];
      observer.onNext(value);
      observer.onCompleted();
      return disposableEmpty;
    }

    return JustObservable;
  }(ObservableBase));

  /**
   *  Returns an observable sequence that contains a single element, using the specified scheduler to send out observer messages.
   *  There is an alias called 'just' or browsers <IE9.
   * @param {Mixed} value Single element in the resulting observable sequence.
   * @param {Scheduler} scheduler Scheduler to send the single element on. If not specified, defaults to Scheduler.immediate.
   * @returns {Observable} An observable sequence containing the single specified element.
   */
  var observableReturn = Observable['return'] = Observable.just = function (value, scheduler) {
    isScheduler(scheduler) || (scheduler = immediateScheduler);
    return new JustObservable(value, scheduler);
  };

  var ThrowObservable = (function(__super__) {
    inherits(ThrowObservable, __super__);
    function ThrowObservable(error, scheduler) {
      this._error = error;
      this._scheduler = scheduler;
      __super__.call(this);
    }

    ThrowObservable.prototype.subscribeCore = function (o) {
      var state = [this._error, o];
      return this._scheduler === immediateScheduler ?
        scheduleItem(null, state) :
        this._scheduler.schedule(state, scheduleItem);
    };

    function scheduleItem(s, state) {
      var e = state[0], o = state[1];
      o.onError(e);
      return disposableEmpty;
    }

    return ThrowObservable;
  }(ObservableBase));

  /**
   *  Returns an observable sequence that terminates with an exception, using the specified scheduler to send out the single onError message.
   *  There is an alias to this method called 'throwError' for browsers <IE9.
   * @param {Mixed} error An object used for the sequence's termination.
   * @param {Scheduler} scheduler Scheduler to send the exceptional termination call on. If not specified, defaults to Scheduler.immediate.
   * @returns {Observable} The observable sequence that terminates exceptionally with the specified exception object.
   */
  var observableThrow = Observable['throw'] = function (error, scheduler) {
    isScheduler(scheduler) || (scheduler = immediateScheduler);
    return new ThrowObservable(error, scheduler);
  };

  var UsingObservable = (function (__super__) {
    inherits(UsingObservable, __super__);
    function UsingObservable(resFn, obsFn) {
      this._resFn = resFn;
      this._obsFn = obsFn;
      __super__.call(this);
    }

    UsingObservable.prototype.subscribeCore = function (o) {
      var disposable = disposableEmpty;
      var resource = tryCatch(this._resFn)();
      if (resource === errorObj) {
        return new BinaryDisposable(observableThrow(resource.e).subscribe(o), disposable);
      }
      resource && (disposable = resource);
      var source = tryCatch(this._obsFn)(resource);
      if (source === errorObj) {
        return new BinaryDisposable(observableThrow(source.e).subscribe(o), disposable);
      }
      return new BinaryDisposable(source.subscribe(o), disposable);
    };

    return UsingObservable;
  }(ObservableBase));

  /**
   * Constructs an observable sequence that depends on a resource object, whose lifetime is tied to the resulting observable sequence's lifetime.
   * @param {Function} resourceFactory Factory function to obtain a resource object.
   * @param {Function} observableFactory Factory function to obtain an observable sequence that depends on the obtained resource.
   * @returns {Observable} An observable sequence whose lifetime controls the lifetime of the dependent resource object.
   */
  Observable.using = function (resourceFactory, observableFactory) {
    return new UsingObservable(resourceFactory, observableFactory);
  };

  /**
   * Propagates the observable sequence or Promise that reacts first.
   * @param {Observable} rightSource Second observable sequence or Promise.
   * @returns {Observable} {Observable} An observable sequence that surfaces either of the given sequences, whichever reacted first.
   */
  observableProto.amb = function (rightSource) {
    var leftSource = this;
    return new AnonymousObservable(function (observer) {
      var choice,
        leftChoice = 'L', rightChoice = 'R',
        leftSubscription = new SingleAssignmentDisposable(),
        rightSubscription = new SingleAssignmentDisposable();

      isPromise(rightSource) && (rightSource = observableFromPromise(rightSource));

      function choiceL() {
        if (!choice) {
          choice = leftChoice;
          rightSubscription.dispose();
        }
      }

      function choiceR() {
        if (!choice) {
          choice = rightChoice;
          leftSubscription.dispose();
        }
      }

      var leftSubscribe = observerCreate(
        function (left) {
          choiceL();
          choice === leftChoice && observer.onNext(left);
        },
        function (e) {
          choiceL();
          choice === leftChoice && observer.onError(e);
        },
        function () {
          choiceL();
          choice === leftChoice && observer.onCompleted();
        }
      );
      var rightSubscribe = observerCreate(
        function (right) {
          choiceR();
          choice === rightChoice && observer.onNext(right);
        },
        function (e) {
          choiceR();
          choice === rightChoice && observer.onError(e);
        },
        function () {
          choiceR();
          choice === rightChoice && observer.onCompleted();
        }
      );

      leftSubscription.setDisposable(leftSource.subscribe(leftSubscribe));
      rightSubscription.setDisposable(rightSource.subscribe(rightSubscribe));

      return new BinaryDisposable(leftSubscription, rightSubscription);
    });
  };

  function amb(p, c) { return p.amb(c); }

  /**
   * Propagates the observable sequence or Promise that reacts first.
   * @returns {Observable} An observable sequence that surfaces any of the given sequences, whichever reacted first.
   */
  Observable.amb = function () {
    var acc = observableNever(), items;
    if (Array.isArray(arguments[0])) {
      items = arguments[0];
    } else {
      var len = arguments.length;
      items = new Array(items);
      for(var i = 0; i < len; i++) { items[i] = arguments[i]; }
    }
    for (var i = 0, len = items.length; i < len; i++) {
      acc = amb(acc, items[i]);
    }
    return acc;
  };

  var CatchObservable = (function (__super__) {
    inherits(CatchObservable, __super__);
    function CatchObservable(source, fn) {
      this.source = source;
      this._fn = fn;
      __super__.call(this);
    }

    CatchObservable.prototype.subscribeCore = function (o) {
      var d1 = new SingleAssignmentDisposable(), subscription = new SerialDisposable();
      subscription.setDisposable(d1);
      d1.setDisposable(this.source.subscribe(new CatchObserver(o, subscription, this._fn)));
      return subscription;
    };

    return CatchObservable;
  }(ObservableBase));

  var CatchObserver = (function(__super__) {
    inherits(CatchObserver, __super__);
    function CatchObserver(o, s, fn) {
      this._o = o;
      this._s = s;
      this._fn = fn;
      __super__.call(this);
    }

    CatchObserver.prototype.next = function (x) { this._o.onNext(x); };
    CatchObserver.prototype.completed = function () { return this._o.onCompleted(); };
    CatchObserver.prototype.error = function (e) {
      var result = tryCatch(this._fn)(e);
      if (result === errorObj) { return this._o.onError(result.e); }
      isPromise(result) && (result = observableFromPromise(result));

      var d = new SingleAssignmentDisposable();
      this._s.setDisposable(d);
      d.setDisposable(result.subscribe(this._o));
    };

    return CatchObserver;
  }(AbstractObserver));

  /**
   * Continues an observable sequence that is terminated by an exception with the next observable sequence.
   * @param {Mixed} handlerOrSecond Exception handler function that returns an observable sequence given the error that occurred in the first sequence, or a second observable sequence used to produce results when an error occurred in the first sequence.
   * @returns {Observable} An observable sequence containing the first sequence's elements, followed by the elements of the handler sequence in case an exception occurred.
   */
  observableProto['catch'] = function (handlerOrSecond) {
    return isFunction(handlerOrSecond) ? new CatchObservable(this, handlerOrSecond) : observableCatch([this, handlerOrSecond]);
  };

  /**
   * Continues an observable sequence that is terminated by an exception with the next observable sequence.
   * @param {Array | Arguments} args Arguments or an array to use as the next sequence if an error occurs.
   * @returns {Observable} An observable sequence containing elements from consecutive source sequences until a source sequence terminates successfully.
   */
  var observableCatch = Observable['catch'] = function () {
    var items;
    if (Array.isArray(arguments[0])) {
      items = arguments[0];
    } else {
      var len = arguments.length;
      items = new Array(len);
      for(var i = 0; i < len; i++) { items[i] = arguments[i]; }
    }
    return enumerableOf(items).catchError();
  };

  /**
   * Merges the specified observable sequences into one observable sequence by using the selector function whenever any of the observable sequences or Promises produces an element.
   * This can be in the form of an argument list of observables or an array.
   *
   * @example
   * 1 - obs = observable.combineLatest(obs1, obs2, obs3, function (o1, o2, o3) { return o1 + o2 + o3; });
   * 2 - obs = observable.combineLatest([obs1, obs2, obs3], function (o1, o2, o3) { return o1 + o2 + o3; });
   * @returns {Observable} An observable sequence containing the result of combining elements of the sources using the specified result selector function.
   */
  observableProto.combineLatest = function () {
    var len = arguments.length, args = new Array(len);
    for(var i = 0; i < len; i++) { args[i] = arguments[i]; }
    if (Array.isArray(args[0])) {
      args[0].unshift(this);
    } else {
      args.unshift(this);
    }
    return combineLatest.apply(this, args);
  };

  function falseFactory() { return false; }
  function argumentsToArray() {
    var len = arguments.length, args = new Array(len);
    for(var i = 0; i < len; i++) { args[i] = arguments[i]; }
    return args;
  }

  var CombineLatestObservable = (function(__super__) {
    inherits(CombineLatestObservable, __super__);
    function CombineLatestObservable(params, cb) {
      this._params = params;
      this._cb = cb;
      __super__.call(this);
    }

    CombineLatestObservable.prototype.subscribeCore = function(observer) {
      var len = this._params.length,
          subscriptions = new Array(len);

      var state = {
        hasValue: arrayInitialize(len, falseFactory),
        hasValueAll: false,
        isDone: arrayInitialize(len, falseFactory),
        values: new Array(len)
      };

      for (var i = 0; i < len; i++) {
        var source = this._params[i], sad = new SingleAssignmentDisposable();
        subscriptions[i] = sad;
        isPromise(source) && (source = observableFromPromise(source));
        sad.setDisposable(source.subscribe(new CombineLatestObserver(observer, i, this._cb, state)));
      }

      return new NAryDisposable(subscriptions);
    };

    return CombineLatestObservable;
  }(ObservableBase));

  var CombineLatestObserver = (function (__super__) {
    inherits(CombineLatestObserver, __super__);
    function CombineLatestObserver(o, i, cb, state) {
      this._o = o;
      this._i = i;
      this._cb = cb;
      this._state = state;
      __super__.call(this);
    }

    function notTheSame(i) {
      return function (x, j) {
        return j !== i;
      };
    }

    CombineLatestObserver.prototype.next = function (x) {
      this._state.values[this._i] = x;
      this._state.hasValue[this._i] = true;
      if (this._state.hasValueAll || (this._state.hasValueAll = this._state.hasValue.every(identity))) {
        var res = tryCatch(this._cb).apply(null, this._state.values);
        if (res === errorObj) { return this._o.onError(res.e); }
        this._o.onNext(res);
      } else if (this._state.isDone.filter(notTheSame(this._i)).every(identity)) {
        this._o.onCompleted();
      }
    };

    CombineLatestObserver.prototype.error = function (e) {
      this._o.onError(e);
    };

    CombineLatestObserver.prototype.completed = function () {
      this._state.isDone[this._i] = true;
      this._state.isDone.every(identity) && this._o.onCompleted();
    };

    return CombineLatestObserver;
  }(AbstractObserver));

  /**
  * Merges the specified observable sequences into one observable sequence by using the selector function whenever any of the observable sequences or Promises produces an element.
  *
  * @example
  * 1 - obs = Rx.Observable.combineLatest(obs1, obs2, obs3, function (o1, o2, o3) { return o1 + o2 + o3; });
  * 2 - obs = Rx.Observable.combineLatest([obs1, obs2, obs3], function (o1, o2, o3) { return o1 + o2 + o3; });
  * @returns {Observable} An observable sequence containing the result of combining elements of the sources using the specified result selector function.
  */
  var combineLatest = Observable.combineLatest = function () {
    var len = arguments.length, args = new Array(len);
    for(var i = 0; i < len; i++) { args[i] = arguments[i]; }
    var resultSelector = isFunction(args[len - 1]) ? args.pop() : argumentsToArray;
    Array.isArray(args[0]) && (args = args[0]);
    return new CombineLatestObservable(args, resultSelector);
  };

  /**
   * Concatenates all the observable sequences.  This takes in either an array or variable arguments to concatenate.
   * @returns {Observable} An observable sequence that contains the elements of each given sequence, in sequential order.
   */
  observableProto.concat = function () {
    for(var args = [], i = 0, len = arguments.length; i < len; i++) { args.push(arguments[i]); }
    args.unshift(this);
    return observableConcat.apply(null, args);
  };

  var ConcatObserver = (function(__super__) {
    inherits(ConcatObserver, __super__);
    function ConcatObserver(s, fn) {
      this._s = s;
      this._fn = fn;
      __super__.call(this);
    }

    ConcatObserver.prototype.next = function (x) { this._s.o.onNext(x); };
    ConcatObserver.prototype.error = function (e) { this._s.o.onError(e); };
    ConcatObserver.prototype.completed = function () { this._s.i++; this._fn(this._s); };

    return ConcatObserver;
  }(AbstractObserver));

  var ConcatObservable = (function(__super__) {
    inherits(ConcatObservable, __super__);
    function ConcatObservable(sources) {
      this._sources = sources;
      __super__.call(this);
    }

    function scheduleRecursive (state, recurse) {
      if (state.disposable.isDisposed) { return; }
      if (state.i === state.sources.length) { return state.o.onCompleted(); }

      // Check if promise
      var currentValue = state.sources[state.i];
      isPromise(currentValue) && (currentValue = observableFromPromise(currentValue));

      var d = new SingleAssignmentDisposable();
      state.subscription.setDisposable(d);
      d.setDisposable(currentValue.subscribe(new ConcatObserver(state, recurse)));
    }

    ConcatObservable.prototype.subscribeCore = function(o) {
      var subscription = new SerialDisposable();
      var disposable = disposableCreate(noop);
      var state = {
        o: o,
        i: 0,
        subscription: subscription,
        disposable: disposable,
        sources: this._sources
      };

      var cancelable = immediateScheduler.scheduleRecursive(state, scheduleRecursive);
      return new NAryDisposable([subscription, disposable, cancelable]);
    };

    return ConcatObservable;
  }(ObservableBase));

  /**
   * Concatenates all the observable sequences.
   * @param {Array | Arguments} args Arguments or an array to concat to the observable sequence.
   * @returns {Observable} An observable sequence that contains the elements of each given sequence, in sequential order.
   */
  var observableConcat = Observable.concat = function () {
    var args;
    if (Array.isArray(arguments[0])) {
      args = arguments[0];
    } else {
      args = new Array(arguments.length);
      for(var i = 0, len = arguments.length; i < len; i++) { args[i] = arguments[i]; }
    }
    return new ConcatObservable(args);
  };

  /**
   * Concatenates an observable sequence of observable sequences.
   * @returns {Observable} An observable sequence that contains the elements of each observed inner sequence, in sequential order.
   */
  observableProto.concatAll = function () {
    return this.merge(1);
  };

  var MergeObservable = (function (__super__) {
    inherits(MergeObservable, __super__);

    function MergeObservable(source, maxConcurrent) {
      this.source = source;
      this.maxConcurrent = maxConcurrent;
      __super__.call(this);
    }

    MergeObservable.prototype.subscribeCore = function(observer) {
      var g = new CompositeDisposable();
      g.add(this.source.subscribe(new MergeObserver(observer, this.maxConcurrent, g)));
      return g;
    };

    return MergeObservable;

  }(ObservableBase));

  var MergeObserver = (function (__super__) {
    function MergeObserver(o, max, g) {
      this.o = o;
      this.max = max;
      this.g = g;
      this.done = false;
      this.q = [];
      this.activeCount = 0;
      __super__.call(this);
    }

    inherits(MergeObserver, __super__);

    MergeObserver.prototype.handleSubscribe = function (xs) {
      var sad = new SingleAssignmentDisposable();
      this.g.add(sad);
      isPromise(xs) && (xs = observableFromPromise(xs));
      sad.setDisposable(xs.subscribe(new InnerObserver(this, sad)));
    };

    MergeObserver.prototype.next = function (innerSource) {
      if(this.activeCount < this.max) {
        this.activeCount++;
        this.handleSubscribe(innerSource);
      } else {
        this.q.push(innerSource);
      }
    };
    MergeObserver.prototype.error = function (e) { this.o.onError(e); };
    MergeObserver.prototype.completed = function () { this.done = true; this.activeCount === 0 && this.o.onCompleted(); };

    function InnerObserver(parent, sad) {
      this.parent = parent;
      this.sad = sad;
      __super__.call(this);
    }

    inherits(InnerObserver, __super__);

    InnerObserver.prototype.next = function (x) { this.parent.o.onNext(x); };
    InnerObserver.prototype.error = function (e) { this.parent.o.onError(e); };
    InnerObserver.prototype.completed = function () {
      this.parent.g.remove(this.sad);
      if (this.parent.q.length > 0) {
        this.parent.handleSubscribe(this.parent.q.shift());
      } else {
        this.parent.activeCount--;
        this.parent.done && this.parent.activeCount === 0 && this.parent.o.onCompleted();
      }
    };

    return MergeObserver;
  }(AbstractObserver));

  /**
  * Merges an observable sequence of observable sequences into an observable sequence, limiting the number of concurrent subscriptions to inner sequences.
  * Or merges two observable sequences into a single observable sequence.
  * @param {Mixed} [maxConcurrentOrOther] Maximum number of inner observable sequences being subscribed to concurrently or the second observable sequence.
  * @returns {Observable} The observable sequence that merges the elements of the inner sequences.
  */
  observableProto.merge = function (maxConcurrentOrOther) {
    return typeof maxConcurrentOrOther !== 'number' ?
      observableMerge(this, maxConcurrentOrOther) :
      new MergeObservable(this, maxConcurrentOrOther);
  };

  /**
   * Merges all the observable sequences into a single observable sequence.
   * The scheduler is optional and if not specified, the immediate scheduler is used.
   * @returns {Observable} The observable sequence that merges the elements of the observable sequences.
   */
  var observableMerge = Observable.merge = function () {
    var scheduler, sources = [], i, len = arguments.length;
    if (!arguments[0]) {
      scheduler = immediateScheduler;
      for(i = 1; i < len; i++) { sources.push(arguments[i]); }
    } else if (isScheduler(arguments[0])) {
      scheduler = arguments[0];
      for(i = 1; i < len; i++) { sources.push(arguments[i]); }
    } else {
      scheduler = immediateScheduler;
      for(i = 0; i < len; i++) { sources.push(arguments[i]); }
    }
    if (Array.isArray(sources[0])) {
      sources = sources[0];
    }
    return observableOf(scheduler, sources).mergeAll();
  };

  var CompositeError = Rx.CompositeError = function(errors) {
    this.innerErrors = errors;
    this.message = 'This contains multiple errors. Check the innerErrors';
    Error.call(this);
  };
  CompositeError.prototype = Object.create(Error.prototype);
  CompositeError.prototype.name = 'CompositeError';

  var MergeDelayErrorObservable = (function(__super__) {
    inherits(MergeDelayErrorObservable, __super__);
    function MergeDelayErrorObservable(source) {
      this.source = source;
      __super__.call(this);
    }

    MergeDelayErrorObservable.prototype.subscribeCore = function (o) {
      var group = new CompositeDisposable(),
        m = new SingleAssignmentDisposable(),
        state = { isStopped: false, errors: [], o: o };

      group.add(m);
      m.setDisposable(this.source.subscribe(new MergeDelayErrorObserver(group, state)));

      return group;
    };

    return MergeDelayErrorObservable;
  }(ObservableBase));

  var MergeDelayErrorObserver = (function(__super__) {
    inherits(MergeDelayErrorObserver, __super__);
    function MergeDelayErrorObserver(group, state) {
      this._group = group;
      this._state = state;
      __super__.call(this);
    }

    function setCompletion(o, errors) {
      if (errors.length === 0) {
        o.onCompleted();
      } else if (errors.length === 1) {
        o.onError(errors[0]);
      } else {
        o.onError(new CompositeError(errors));
      }
    }

    MergeDelayErrorObserver.prototype.next = function (x) {
      var inner = new SingleAssignmentDisposable();
      this._group.add(inner);

      // Check for promises support
      isPromise(x) && (x = observableFromPromise(x));
      inner.setDisposable(x.subscribe(new InnerObserver(inner, this._group, this._state)));
    };

    MergeDelayErrorObserver.prototype.error = function (e) {
      this._state.errors.push(e);
      this._state.isStopped = true;
      this._group.length === 1 && setCompletion(this._state.o, this._state.errors);
    };

    MergeDelayErrorObserver.prototype.completed = function () {
      this._state.isStopped = true;
      this._group.length === 1 && setCompletion(this._state.o, this._state.errors);
    };

    inherits(InnerObserver, __super__);
    function InnerObserver(inner, group, state) {
      this._inner = inner;
      this._group = group;
      this._state = state;
      __super__.call(this);
    }

    InnerObserver.prototype.next = function (x) { this._state.o.onNext(x); };
    InnerObserver.prototype.error = function (e) {
      this._state.errors.push(e);
      this._group.remove(this._inner);
      this._state.isStopped && this._group.length === 1 && setCompletion(this._state.o, this._state.errors);
    };
    InnerObserver.prototype.completed = function () {
      this._group.remove(this._inner);
      this._state.isStopped && this._group.length === 1 && setCompletion(this._state.o, this._state.errors);
    };

    return MergeDelayErrorObserver;
  }(AbstractObserver));

  /**
  * Flattens an Observable that emits Observables into one Observable, in a way that allows an Observer to
  * receive all successfully emitted items from all of the source Observables without being interrupted by
  * an error notification from one of them.
  *
  * This behaves like Observable.prototype.mergeAll except that if any of the merged Observables notify of an
  * error via the Observer's onError, mergeDelayError will refrain from propagating that
  * error notification until all of the merged Observables have finished emitting items.
  * @param {Array | Arguments} args Arguments or an array to merge.
  * @returns {Observable} an Observable that emits all of the items emitted by the Observables emitted by the Observable
  */
  Observable.mergeDelayError = function() {
    var args;
    if (Array.isArray(arguments[0])) {
      args = arguments[0];
    } else {
      var len = arguments.length;
      args = new Array(len);
      for(var i = 0; i < len; i++) { args[i] = arguments[i]; }
    }
    var source = observableOf(null, args);
    return new MergeDelayErrorObservable(source);
  };

  var MergeAllObservable = (function (__super__) {
    inherits(MergeAllObservable, __super__);

    function MergeAllObservable(source) {
      this.source = source;
      __super__.call(this);
    }

    MergeAllObservable.prototype.subscribeCore = function (o) {
      var g = new CompositeDisposable(), m = new SingleAssignmentDisposable();
      g.add(m);
      m.setDisposable(this.source.subscribe(new MergeAllObserver(o, g)));
      return g;
    };

    return MergeAllObservable;
  }(ObservableBase));

  var MergeAllObserver = (function (__super__) {
    function MergeAllObserver(o, g) {
      this.o = o;
      this.g = g;
      this.done = false;
      __super__.call(this);
    }

    inherits(MergeAllObserver, __super__);

    MergeAllObserver.prototype.next = function(innerSource) {
      var sad = new SingleAssignmentDisposable();
      this.g.add(sad);
      isPromise(innerSource) && (innerSource = observableFromPromise(innerSource));
      sad.setDisposable(innerSource.subscribe(new InnerObserver(this, sad)));
    };

    MergeAllObserver.prototype.error = function (e) {
      this.o.onError(e);
    };

    MergeAllObserver.prototype.completed = function () {
      this.done = true;
      this.g.length === 1 && this.o.onCompleted();
    };

    function InnerObserver(parent, sad) {
      this.parent = parent;
      this.sad = sad;
      __super__.call(this);
    }

    inherits(InnerObserver, __super__);

    InnerObserver.prototype.next = function (x) {
      this.parent.o.onNext(x);
    };
    InnerObserver.prototype.error = function (e) {
      this.parent.o.onError(e);
    };
    InnerObserver.prototype.completed = function () {
      this.parent.g.remove(this.sad);
      this.parent.done && this.parent.g.length === 1 && this.parent.o.onCompleted();
    };

    return MergeAllObserver;
  }(AbstractObserver));

  /**
  * Merges an observable sequence of observable sequences into an observable sequence.
  * @returns {Observable} The observable sequence that merges the elements of the inner sequences.
  */
  observableProto.mergeAll = function () {
    return new MergeAllObservable(this);
  };

  /**
   * Continues an observable sequence that is terminated normally or by an exception with the next observable sequence.
   * @param {Observable} second Second observable sequence used to produce results after the first sequence terminates.
   * @returns {Observable} An observable sequence that concatenates the first and second sequence, even if the first sequence terminates exceptionally.
   */
  observableProto.onErrorResumeNext = function (second) {
    if (!second) { throw new Error('Second observable is required'); }
    return onErrorResumeNext([this, second]);
  };

  var OnErrorResumeNextObservable = (function(__super__) {
    inherits(OnErrorResumeNextObservable, __super__);
    function OnErrorResumeNextObservable(sources) {
      this.sources = sources;
      __super__.call(this);
    }

    function scheduleMethod(state, recurse) {
      if (state.pos < state.sources.length) {
        var current = state.sources[state.pos++];
        isPromise(current) && (current = observableFromPromise(current));
        var d = new SingleAssignmentDisposable();
        state.subscription.setDisposable(d);
        d.setDisposable(current.subscribe(new OnErrorResumeNextObserver(state, recurse)));
      } else {
        state.o.onCompleted();
      }
    }

    OnErrorResumeNextObservable.prototype.subscribeCore = function (o) {
      var subscription = new SerialDisposable(),
          state = {pos: 0, subscription: subscription, o: o, sources: this.sources },
          cancellable = immediateScheduler.scheduleRecursive(state, scheduleMethod);

      return new BinaryDisposable(subscription, cancellable);
    };

    return OnErrorResumeNextObservable;
  }(ObservableBase));

  var OnErrorResumeNextObserver = (function(__super__) {
    inherits(OnErrorResumeNextObserver, __super__);
    function OnErrorResumeNextObserver(state, recurse) {
      this._state = state;
      this._recurse = recurse;
      __super__.call(this);
    }

    OnErrorResumeNextObserver.prototype.next = function (x) { this._state.o.onNext(x); };
    OnErrorResumeNextObserver.prototype.error = function () { this._recurse(this._state); };
    OnErrorResumeNextObserver.prototype.completed = function () { this._recurse(this._state); };

    return OnErrorResumeNextObserver;
  }(AbstractObserver));

  /**
   * Continues an observable sequence that is terminated normally or by an exception with the next observable sequence.
   * @returns {Observable} An observable sequence that concatenates the source sequences, even if a sequence terminates exceptionally.
   */
  var onErrorResumeNext = Observable.onErrorResumeNext = function () {
    var sources = [];
    if (Array.isArray(arguments[0])) {
      sources = arguments[0];
    } else {
      var len = arguments.length;
      sources = new Array(len);
      for(var i = 0; i < len; i++) { sources[i] = arguments[i]; }
    }
    return new OnErrorResumeNextObservable(sources);
  };

  var SkipUntilObservable = (function(__super__) {
    inherits(SkipUntilObservable, __super__);

    function SkipUntilObservable(source, other) {
      this._s = source;
      this._o = isPromise(other) ? observableFromPromise(other) : other;
      this._open = false;
      __super__.call(this);
    }

    SkipUntilObservable.prototype.subscribeCore = function(o) {
      var leftSubscription = new SingleAssignmentDisposable();
      leftSubscription.setDisposable(this._s.subscribe(new SkipUntilSourceObserver(o, this)));

      isPromise(this._o) && (this._o = observableFromPromise(this._o));

      var rightSubscription = new SingleAssignmentDisposable();
      rightSubscription.setDisposable(this._o.subscribe(new SkipUntilOtherObserver(o, this, rightSubscription)));

      return new BinaryDisposable(leftSubscription, rightSubscription);
    };

    return SkipUntilObservable;
  }(ObservableBase));

  var SkipUntilSourceObserver = (function(__super__) {
    inherits(SkipUntilSourceObserver, __super__);
    function SkipUntilSourceObserver(o, p) {
      this._o = o;
      this._p = p;
      __super__.call(this);
    }

    SkipUntilSourceObserver.prototype.next = function (x) {
      this._p._open && this._o.onNext(x);
    };

    SkipUntilSourceObserver.prototype.error = function (err) {
      this._o.onError(err);
    };

    SkipUntilSourceObserver.prototype.onCompleted = function () {
      this._p._open && this._o.onCompleted();
    };

    return SkipUntilSourceObserver;
  }(AbstractObserver));

  var SkipUntilOtherObserver = (function(__super__) {
    inherits(SkipUntilOtherObserver, __super__);
    function SkipUntilOtherObserver(o, p, r) {
      this._o = o;
      this._p = p;
      this._r = r;
      __super__.call(this);
    }

    SkipUntilOtherObserver.prototype.next = function () {
      this._p._open = true;
      this._r.dispose();
    };

    SkipUntilOtherObserver.prototype.error = function (err) {
      this._o.onError(err);
    };

    SkipUntilOtherObserver.prototype.onCompleted = function () {
      this._r.dispose();
    };

    return SkipUntilOtherObserver;
  }(AbstractObserver));

  /**
   * Returns the values from the source observable sequence only after the other observable sequence produces a value.
   * @param {Observable | Promise} other The observable sequence or Promise that triggers propagation of elements of the source sequence.
   * @returns {Observable} An observable sequence containing the elements of the source sequence starting from the point the other sequence triggered propagation.
   */
  observableProto.skipUntil = function (other) {
    return new SkipUntilObservable(this, other);
  };

  var SwitchObservable = (function(__super__) {
    inherits(SwitchObservable, __super__);
    function SwitchObservable(source) {
      this.source = source;
      __super__.call(this);
    }

    SwitchObservable.prototype.subscribeCore = function (o) {
      var inner = new SerialDisposable(), s = this.source.subscribe(new SwitchObserver(o, inner));
      return new BinaryDisposable(s, inner);
    };

    inherits(SwitchObserver, AbstractObserver);
    function SwitchObserver(o, inner) {
      this.o = o;
      this.inner = inner;
      this.stopped = false;
      this.latest = 0;
      this.hasLatest = false;
      AbstractObserver.call(this);
    }

    SwitchObserver.prototype.next = function (innerSource) {
      var d = new SingleAssignmentDisposable(), id = ++this.latest;
      this.hasLatest = true;
      this.inner.setDisposable(d);
      isPromise(innerSource) && (innerSource = observableFromPromise(innerSource));
      d.setDisposable(innerSource.subscribe(new InnerObserver(this, id)));
    };

    SwitchObserver.prototype.error = function (e) {
      this.o.onError(e);
    };

    SwitchObserver.prototype.completed = function () {
      this.stopped = true;
      !this.hasLatest && this.o.onCompleted();
    };

    inherits(InnerObserver, AbstractObserver);
    function InnerObserver(parent, id) {
      this.parent = parent;
      this.id = id;
      AbstractObserver.call(this);
    }
    InnerObserver.prototype.next = function (x) {
      this.parent.latest === this.id && this.parent.o.onNext(x);
    };

    InnerObserver.prototype.error = function (e) {
      this.parent.latest === this.id && this.parent.o.onError(e);
    };

    InnerObserver.prototype.completed = function () {
      if (this.parent.latest === this.id) {
        this.parent.hasLatest = false;
        this.parent.stopped && this.parent.o.onCompleted();
      }
    };

    return SwitchObservable;
  }(ObservableBase));

  /**
  * Transforms an observable sequence of observable sequences into an observable sequence producing values only from the most recent observable sequence.
  * @returns {Observable} The observable sequence that at any point in time produces the elements of the most recent inner observable sequence that has been received.
  */
  observableProto['switch'] = observableProto.switchLatest = function () {
    return new SwitchObservable(this);
  };

  var TakeUntilObservable = (function(__super__) {
    inherits(TakeUntilObservable, __super__);

    function TakeUntilObservable(source, other) {
      this.source = source;
      this.other = isPromise(other) ? observableFromPromise(other) : other;
      __super__.call(this);
    }

    TakeUntilObservable.prototype.subscribeCore = function(o) {
      return new BinaryDisposable(
        this.source.subscribe(o),
        this.other.subscribe(new TakeUntilObserver(o))
      );
    };

    return TakeUntilObservable;
  }(ObservableBase));

  var TakeUntilObserver = (function(__super__) {
    inherits(TakeUntilObserver, __super__);
    function TakeUntilObserver(o) {
      this._o = o;
      __super__.call(this);
    }

    TakeUntilObserver.prototype.next = function () {
      this._o.onCompleted();
    };

    TakeUntilObserver.prototype.error = function (err) {
      this._o.onError(err);
    };

    TakeUntilObserver.prototype.onCompleted = noop;

    return TakeUntilObserver;
  }(AbstractObserver));

  /**
   * Returns the values from the source observable sequence until the other observable sequence produces a value.
   * @param {Observable | Promise} other Observable sequence or Promise that terminates propagation of elements of the source sequence.
   * @returns {Observable} An observable sequence containing the elements of the source sequence up to the point the other sequence interrupted further propagation.
   */
  observableProto.takeUntil = function (other) {
    return new TakeUntilObservable(this, other);
  };

  function falseFactory() { return false; }
  function argumentsToArray() {
    var len = arguments.length, args = new Array(len);
    for(var i = 0; i < len; i++) { args[i] = arguments[i]; }
    return args;
  }

  var WithLatestFromObservable = (function(__super__) {
    inherits(WithLatestFromObservable, __super__);
    function WithLatestFromObservable(source, sources, resultSelector) {
      this._s = source;
      this._ss = sources;
      this._cb = resultSelector;
      __super__.call(this);
    }

    WithLatestFromObservable.prototype.subscribeCore = function (o) {
      var len = this._ss.length;
      var state = {
        hasValue: arrayInitialize(len, falseFactory),
        hasValueAll: false,
        values: new Array(len)
      };

      var n = this._ss.length, subscriptions = new Array(n + 1);
      for (var i = 0; i < n; i++) {
        var other = this._ss[i], sad = new SingleAssignmentDisposable();
        isPromise(other) && (other = observableFromPromise(other));
        sad.setDisposable(other.subscribe(new WithLatestFromOtherObserver(o, i, state)));
        subscriptions[i] = sad;
      }

      var outerSad = new SingleAssignmentDisposable();
      outerSad.setDisposable(this._s.subscribe(new WithLatestFromSourceObserver(o, this._cb, state)));
      subscriptions[n] = outerSad;

      return new NAryDisposable(subscriptions);
    };

    return WithLatestFromObservable;
  }(ObservableBase));

  var WithLatestFromOtherObserver = (function (__super__) {
    inherits(WithLatestFromOtherObserver, __super__);
    function WithLatestFromOtherObserver(o, i, state) {
      this._o = o;
      this._i = i;
      this._state = state;
      __super__.call(this);
    }

    WithLatestFromOtherObserver.prototype.next = function (x) {
      this._state.values[this._i] = x;
      this._state.hasValue[this._i] = true;
      this._state.hasValueAll = this._state.hasValue.every(identity);
    };

    WithLatestFromOtherObserver.prototype.error = function (e) {
      this._o.onError(e);
    };

    WithLatestFromOtherObserver.prototype.completed = noop;

    return WithLatestFromOtherObserver;
  }(AbstractObserver));

  var WithLatestFromSourceObserver = (function (__super__) {
    inherits(WithLatestFromSourceObserver, __super__);
    function WithLatestFromSourceObserver(o, cb, state) {
      this._o = o;
      this._cb = cb;
      this._state = state;
      __super__.call(this);
    }

    WithLatestFromSourceObserver.prototype.next = function (x) {
      var allValues = [x].concat(this._state.values);
      if (!this._state.hasValueAll) { return; }
      var res = tryCatch(this._cb).apply(null, allValues);
      if (res === errorObj) { return this._o.onError(res.e); }
      this._o.onNext(res);
    };

    WithLatestFromSourceObserver.prototype.error = function (e) {
      this._o.onError(e);
    };

    WithLatestFromSourceObserver.prototype.completed = function () {
      this._o.onCompleted();
    };

    return WithLatestFromSourceObserver;
  }(AbstractObserver));

  /**
   * Merges the specified observable sequences into one observable sequence by using the selector function only when the (first) source observable sequence produces an element.
   * @returns {Observable} An observable sequence containing the result of combining elements of the sources using the specified result selector function.
   */
  observableProto.withLatestFrom = function () {
    if (arguments.length === 0) { throw new Error('invalid arguments'); }

    var len = arguments.length, args = new Array(len);
    for(var i = 0; i < len; i++) { args[i] = arguments[i]; }
    var resultSelector = isFunction(args[len - 1]) ? args.pop() : argumentsToArray;
    Array.isArray(args[0]) && (args = args[0]);

    return new WithLatestFromObservable(this, args, resultSelector);
  };

  function falseFactory() { return false; }
  function emptyArrayFactory() { return []; }

  var ZipObservable = (function(__super__) {
    inherits(ZipObservable, __super__);
    function ZipObservable(sources, resultSelector) {
      this._s = sources;
      this._cb = resultSelector;
      __super__.call(this);
    }

    ZipObservable.prototype.subscribeCore = function(observer) {
      var n = this._s.length,
          subscriptions = new Array(n),
          done = arrayInitialize(n, falseFactory),
          q = arrayInitialize(n, emptyArrayFactory);

      for (var i = 0; i < n; i++) {
        var source = this._s[i], sad = new SingleAssignmentDisposable();
        subscriptions[i] = sad;
        isPromise(source) && (source = observableFromPromise(source));
        sad.setDisposable(source.subscribe(new ZipObserver(observer, i, this, q, done)));
      }

      return new NAryDisposable(subscriptions);
    };

    return ZipObservable;
  }(ObservableBase));

  var ZipObserver = (function (__super__) {
    inherits(ZipObserver, __super__);
    function ZipObserver(o, i, p, q, d) {
      this._o = o;
      this._i = i;
      this._p = p;
      this._q = q;
      this._d = d;
      __super__.call(this);
    }

    function notEmpty(x) { return x.length > 0; }
    function shiftEach(x) { return x.shift(); }
    function notTheSame(i) {
      return function (x, j) {
        return j !== i;
      };
    }

    ZipObserver.prototype.next = function (x) {
      this._q[this._i].push(x);
      if (this._q.every(notEmpty)) {
        var queuedValues = this._q.map(shiftEach);
        var res = tryCatch(this._p._cb).apply(null, queuedValues);
        if (res === errorObj) { return this._o.onError(res.e); }
        this._o.onNext(res);
      } else if (this._d.filter(notTheSame(this._i)).every(identity)) {
        this._o.onCompleted();
      }
    };

    ZipObserver.prototype.error = function (e) {
      this._o.onError(e);
    };

    ZipObserver.prototype.completed = function () {
      this._d[this._i] = true;
      this._d.every(identity) && this._o.onCompleted();
    };

    return ZipObserver;
  }(AbstractObserver));

  /**
   * Merges the specified observable sequences into one observable sequence by using the selector function whenever all of the observable sequences or an array have produced an element at a corresponding index.
   * The last element in the arguments must be a function to invoke for each series of elements at corresponding indexes in the args.
   * @returns {Observable} An observable sequence containing the result of combining elements of the args using the specified result selector function.
   */
  observableProto.zip = function () {
    if (arguments.length === 0) { throw new Error('invalid arguments'); }

    var len = arguments.length, args = new Array(len);
    for(var i = 0; i < len; i++) { args[i] = arguments[i]; }
    var resultSelector = isFunction(args[len - 1]) ? args.pop() : argumentsToArray;
    Array.isArray(args[0]) && (args = args[0]);

    var parent = this;
    args.unshift(parent);

    return new ZipObservable(args, resultSelector);
  };

  /**
   * Merges the specified observable sequences into one observable sequence by using the selector function whenever all of the observable sequences have produced an element at a corresponding index.
   * @param arguments Observable sources.
   * @param {Function} resultSelector Function to invoke for each series of elements at corresponding indexes in the sources.
   * @returns {Observable} An observable sequence containing the result of combining elements of the sources using the specified result selector function.
   */
  Observable.zip = function () {
    var len = arguments.length, args = new Array(len);
    for(var i = 0; i < len; i++) { args[i] = arguments[i]; }
    if (Array.isArray(args[0])) {
      args = isFunction(args[1]) ? args[0].concat(args[1]) : args[0];
    }
    var first = args.shift();
    return first.zip.apply(first, args);
  };

function falseFactory() { return false; }
function emptyArrayFactory() { return []; }
function argumentsToArray() {
  var len = arguments.length, args = new Array(len);
  for(var i = 0; i < len; i++) { args[i] = arguments[i]; }
  return args;
}

var ZipIterableObservable = (function(__super__) {
  inherits(ZipIterableObservable, __super__);
  function ZipIterableObservable(sources, cb) {
    this.sources = sources;
    this._cb = cb;
    __super__.call(this);
  }

  ZipIterableObservable.prototype.subscribeCore = function (o) {
    var sources = this.sources, len = sources.length, subscriptions = new Array(len);

    var state = {
      q: arrayInitialize(len, emptyArrayFactory),
      done: arrayInitialize(len, falseFactory),
      cb: this._cb,
      o: o
    };

    for (var i = 0; i < len; i++) {
      (function (i) {
        var source = sources[i], sad = new SingleAssignmentDisposable();
        (isArrayLike(source) || isIterable(source)) && (source = observableFrom(source));

        subscriptions[i] = sad;
        sad.setDisposable(source.subscribe(new ZipIterableObserver(state, i)));
      }(i));
    }

    return new NAryDisposable(subscriptions);
  };

  return ZipIterableObservable;
}(ObservableBase));

var ZipIterableObserver = (function (__super__) {
  inherits(ZipIterableObserver, __super__);
  function ZipIterableObserver(s, i) {
    this._s = s;
    this._i = i;
    __super__.call(this);
  }

  function notEmpty(x) { return x.length > 0; }
  function shiftEach(x) { return x.shift(); }
  function notTheSame(i) {
    return function (x, j) {
      return j !== i;
    };
  }

  ZipIterableObserver.prototype.next = function (x) {
    this._s.q[this._i].push(x);
    if (this._s.q.every(notEmpty)) {
      var queuedValues = this._s.q.map(shiftEach),
          res = tryCatch(this._s.cb).apply(null, queuedValues);
      if (res === errorObj) { return this._s.o.onError(res.e); }
      this._s.o.onNext(res);
    } else if (this._s.done.filter(notTheSame(this._i)).every(identity)) {
      this._s.o.onCompleted();
    }
  };

  ZipIterableObserver.prototype.error = function (e) { this._s.o.onError(e); };

  ZipIterableObserver.prototype.completed = function () {
    this._s.done[this._i] = true;
    this._s.done.every(identity) && this._s.o.onCompleted();
  };

  return ZipIterableObserver;
}(AbstractObserver));

/**
 * Merges the specified observable sequences into one observable sequence by using the selector function whenever all of the observable sequences or an array have produced an element at a corresponding index.
 * The last element in the arguments must be a function to invoke for each series of elements at corresponding indexes in the args.
 * @returns {Observable} An observable sequence containing the result of combining elements of the args using the specified result selector function.
 */
observableProto.zipIterable = function () {
  if (arguments.length === 0) { throw new Error('invalid arguments'); }

  var len = arguments.length, args = new Array(len);
  for(var i = 0; i < len; i++) { args[i] = arguments[i]; }
  var resultSelector = isFunction(args[len - 1]) ? args.pop() : argumentsToArray;

  var parent = this;
  args.unshift(parent);
  return new ZipIterableObservable(args, resultSelector);
};

  function asObservable(source) {
    return function subscribe(o) { return source.subscribe(o); };
  }

  /**
   *  Hides the identity of an observable sequence.
   * @returns {Observable} An observable sequence that hides the identity of the source sequence.
   */
  observableProto.asObservable = function () {
    return new AnonymousObservable(asObservable(this), this);
  };

  function toArray(x) { return x.toArray(); }
  function notEmpty(x) { return x.length > 0; }

  /**
   *  Projects each element of an observable sequence into zero or more buffers which are produced based on element count information.
   * @param {Number} count Length of each buffer.
   * @param {Number} [skip] Number of elements to skip between creation of consecutive buffers. If not provided, defaults to the count.
   * @returns {Observable} An observable sequence of buffers.
   */
  observableProto.bufferWithCount = function (count, skip) {
    typeof skip !== 'number' && (skip = count);
    return this.windowWithCount(count, skip)
      .flatMap(toArray)
      .filter(notEmpty);
  };

  var DematerializeObservable = (function (__super__) {
    inherits(DematerializeObservable, __super__);
    function DematerializeObservable(source) {
      this.source = source;
      __super__.call(this);
    }

    DematerializeObservable.prototype.subscribeCore = function (o) {
      return this.source.subscribe(new DematerializeObserver(o));
    };

    return DematerializeObservable;
  }(ObservableBase));

  var DematerializeObserver = (function (__super__) {
    inherits(DematerializeObserver, __super__);

    function DematerializeObserver(o) {
      this._o = o;
      __super__.call(this);
    }

    DematerializeObserver.prototype.next = function (x) { x.accept(this._o); };
    DematerializeObserver.prototype.error = function (e) { this._o.onError(e); };
    DematerializeObserver.prototype.completed = function () { this._o.onCompleted(); };

    return DematerializeObserver;
  }(AbstractObserver));

  /**
   * Dematerializes the explicit notification values of an observable sequence as implicit notifications.
   * @returns {Observable} An observable sequence exhibiting the behavior corresponding to the source sequence's notification values.
   */
  observableProto.dematerialize = function () {
    return new DematerializeObservable(this);
  };

  var DistinctUntilChangedObservable = (function(__super__) {
    inherits(DistinctUntilChangedObservable, __super__);
    function DistinctUntilChangedObservable(source, keyFn, comparer) {
      this.source = source;
      this.keyFn = keyFn;
      this.comparer = comparer;
      __super__.call(this);
    }

    DistinctUntilChangedObservable.prototype.subscribeCore = function (o) {
      return this.source.subscribe(new DistinctUntilChangedObserver(o, this.keyFn, this.comparer));
    };

    return DistinctUntilChangedObservable;
  }(ObservableBase));

  var DistinctUntilChangedObserver = (function(__super__) {
    inherits(DistinctUntilChangedObserver, __super__);
    function DistinctUntilChangedObserver(o, keyFn, comparer) {
      this.o = o;
      this.keyFn = keyFn;
      this.comparer = comparer;
      this.hasCurrentKey = false;
      this.currentKey = null;
      __super__.call(this);
    }

    DistinctUntilChangedObserver.prototype.next = function (x) {
      var key = x, comparerEquals;
      if (isFunction(this.keyFn)) {
        key = tryCatch(this.keyFn)(x);
        if (key === errorObj) { return this.o.onError(key.e); }
      }
      if (this.hasCurrentKey) {
        comparerEquals = tryCatch(this.comparer)(this.currentKey, key);
        if (comparerEquals === errorObj) { return this.o.onError(comparerEquals.e); }
      }
      if (!this.hasCurrentKey || !comparerEquals) {
        this.hasCurrentKey = true;
        this.currentKey = key;
        this.o.onNext(x);
      }
    };
    DistinctUntilChangedObserver.prototype.error = function(e) {
      this.o.onError(e);
    };
    DistinctUntilChangedObserver.prototype.completed = function () {
      this.o.onCompleted();
    };

    return DistinctUntilChangedObserver;
  }(AbstractObserver));

  /**
  *  Returns an observable sequence that contains only distinct contiguous elements according to the keyFn and the comparer.
  * @param {Function} [keyFn] A function to compute the comparison key for each element. If not provided, it projects the value.
  * @param {Function} [comparer] Equality comparer for computed key values. If not provided, defaults to an equality comparer function.
  * @returns {Observable} An observable sequence only containing the distinct contiguous elements, based on a computed key value, from the source sequence.
  */
  observableProto.distinctUntilChanged = function (keyFn, comparer) {
    comparer || (comparer = defaultComparer);
    return new DistinctUntilChangedObservable(this, keyFn, comparer);
  };

  var TapObservable = (function(__super__) {
    inherits(TapObservable,__super__);
    function TapObservable(source, observerOrOnNext, onError, onCompleted) {
      this.source = source;
      this._oN = observerOrOnNext;
      this._oE = onError;
      this._oC = onCompleted;
      __super__.call(this);
    }

    TapObservable.prototype.subscribeCore = function(o) {
      return this.source.subscribe(new InnerObserver(o, this));
    };

    inherits(InnerObserver, AbstractObserver);
    function InnerObserver(o, p) {
      this.o = o;
      this.t = !p._oN || isFunction(p._oN) ?
        observerCreate(p._oN || noop, p._oE || noop, p._oC || noop) :
        p._oN;
      this.isStopped = false;
      AbstractObserver.call(this);
    }
    InnerObserver.prototype.next = function(x) {
      var res = tryCatch(this.t.onNext).call(this.t, x);
      if (res === errorObj) { this.o.onError(res.e); }
      this.o.onNext(x);
    };
    InnerObserver.prototype.error = function(err) {
      var res = tryCatch(this.t.onError).call(this.t, err);
      if (res === errorObj) { return this.o.onError(res.e); }
      this.o.onError(err);
    };
    InnerObserver.prototype.completed = function() {
      var res = tryCatch(this.t.onCompleted).call(this.t);
      if (res === errorObj) { return this.o.onError(res.e); }
      this.o.onCompleted();
    };

    return TapObservable;
  }(ObservableBase));

  /**
  *  Invokes an action for each element in the observable sequence and invokes an action upon graceful or exceptional termination of the observable sequence.
  *  This method can be used for debugging, logging, etc. of query behavior by intercepting the message stream to run arbitrary actions for messages on the pipeline.
  * @param {Function | Observer} observerOrOnNext Action to invoke for each element in the observable sequence or an o.
  * @param {Function} [onError]  Action to invoke upon exceptional termination of the observable sequence. Used if only the observerOrOnNext parameter is also a function.
  * @param {Function} [onCompleted]  Action to invoke upon graceful termination of the observable sequence. Used if only the observerOrOnNext parameter is also a function.
  * @returns {Observable} The source sequence with the side-effecting behavior applied.
  */
  observableProto['do'] = observableProto.tap = observableProto.doAction = function (observerOrOnNext, onError, onCompleted) {
    return new TapObservable(this, observerOrOnNext, onError, onCompleted);
  };

  /**
  *  Invokes an action for each element in the observable sequence.
  *  This method can be used for debugging, logging, etc. of query behavior by intercepting the message stream to run arbitrary actions for messages on the pipeline.
  * @param {Function} onNext Action to invoke for each element in the observable sequence.
  * @param {Any} [thisArg] Object to use as this when executing callback.
  * @returns {Observable} The source sequence with the side-effecting behavior applied.
  */
  observableProto.doOnNext = observableProto.tapOnNext = function (onNext, thisArg) {
    return this.tap(typeof thisArg !== 'undefined' ? function (x) { onNext.call(thisArg, x); } : onNext);
  };

  /**
  *  Invokes an action upon exceptional termination of the observable sequence.
  *  This method can be used for debugging, logging, etc. of query behavior by intercepting the message stream to run arbitrary actions for messages on the pipeline.
  * @param {Function} onError Action to invoke upon exceptional termination of the observable sequence.
  * @param {Any} [thisArg] Object to use as this when executing callback.
  * @returns {Observable} The source sequence with the side-effecting behavior applied.
  */
  observableProto.doOnError = observableProto.tapOnError = function (onError, thisArg) {
    return this.tap(noop, typeof thisArg !== 'undefined' ? function (e) { onError.call(thisArg, e); } : onError);
  };

  /**
  *  Invokes an action upon graceful termination of the observable sequence.
  *  This method can be used for debugging, logging, etc. of query behavior by intercepting the message stream to run arbitrary actions for messages on the pipeline.
  * @param {Function} onCompleted Action to invoke upon graceful termination of the observable sequence.
  * @param {Any} [thisArg] Object to use as this when executing callback.
  * @returns {Observable} The source sequence with the side-effecting behavior applied.
  */
  observableProto.doOnCompleted = observableProto.tapOnCompleted = function (onCompleted, thisArg) {
    return this.tap(noop, null, typeof thisArg !== 'undefined' ? function () { onCompleted.call(thisArg); } : onCompleted);
  };

  var FinallyObservable = (function (__super__) {
    inherits(FinallyObservable, __super__);
    function FinallyObservable(source, fn, thisArg) {
      this.source = source;
      this._fn = bindCallback(fn, thisArg, 0);
      __super__.call(this);
    }

    FinallyObservable.prototype.subscribeCore = function (o) {
      var d = tryCatch(this.source.subscribe).call(this.source, o);
      if (d === errorObj) {
        this._fn();
        thrower(d.e);
      }

      return new FinallyDisposable(d, this._fn);
    };

    function FinallyDisposable(s, fn) {
      this.isDisposed = false;
      this._s = s;
      this._fn = fn;
    }
    FinallyDisposable.prototype.dispose = function () {
      if (!this.isDisposed) {
        var res = tryCatch(this._s.dispose).call(this._s);
        this._fn();
        res === errorObj && thrower(res.e);
      }
    };

    return FinallyObservable;

  }(ObservableBase));

  /**
   *  Invokes a specified action after the source observable sequence terminates gracefully or exceptionally.
   * @param {Function} finallyAction Action to invoke after the source observable sequence terminates.
   * @returns {Observable} Source sequence with the action-invoking termination behavior applied.
   */
  observableProto['finally'] = function (action, thisArg) {
    return new FinallyObservable(this, action, thisArg);
  };

  var IgnoreElementsObservable = (function(__super__) {
    inherits(IgnoreElementsObservable, __super__);

    function IgnoreElementsObservable(source) {
      this.source = source;
      __super__.call(this);
    }

    IgnoreElementsObservable.prototype.subscribeCore = function (o) {
      return this.source.subscribe(new InnerObserver(o));
    };

    function InnerObserver(o) {
      this.o = o;
      this.isStopped = false;
    }
    InnerObserver.prototype.onNext = noop;
    InnerObserver.prototype.onError = function (err) {
      if(!this.isStopped) {
        this.isStopped = true;
        this.o.onError(err);
      }
    };
    InnerObserver.prototype.onCompleted = function () {
      if(!this.isStopped) {
        this.isStopped = true;
        this.o.onCompleted();
      }
    };
    InnerObserver.prototype.dispose = function() { this.isStopped = true; };
    InnerObserver.prototype.fail = function (e) {
      if (!this.isStopped) {
        this.isStopped = true;
        this.observer.onError(e);
        return true;
      }

      return false;
    };

    return IgnoreElementsObservable;
  }(ObservableBase));

  /**
   *  Ignores all elements in an observable sequence leaving only the termination messages.
   * @returns {Observable} An empty observable sequence that signals termination, successful or exceptional, of the source sequence.
   */
  observableProto.ignoreElements = function () {
    return new IgnoreElementsObservable(this);
  };

  var MaterializeObservable = (function (__super__) {
    inherits(MaterializeObservable, __super__);
    function MaterializeObservable(source, fn) {
      this.source = source;
      __super__.call(this);
    }

    MaterializeObservable.prototype.subscribeCore = function (o) {
      return this.source.subscribe(new MaterializeObserver(o));
    };

    return MaterializeObservable;
  }(ObservableBase));

  var MaterializeObserver = (function (__super__) {
    inherits(MaterializeObserver, __super__);

    function MaterializeObserver(o) {
      this._o = o;
      __super__.call(this);
    }

    MaterializeObserver.prototype.next = function (x) { this._o.onNext(notificationCreateOnNext(x)) };
    MaterializeObserver.prototype.error = function (e) { this._o.onNext(notificationCreateOnError(e)); this._o.onCompleted(); };
    MaterializeObserver.prototype.completed = function () { this._o.onNext(notificationCreateOnCompleted()); this._o.onCompleted(); };

    return MaterializeObserver;
  }(AbstractObserver));

  /**
   *  Materializes the implicit notifications of an observable sequence as explicit notification values.
   * @returns {Observable} An observable sequence containing the materialized notification values from the source sequence.
   */
  observableProto.materialize = function () {
    return new MaterializeObservable(this);
  };

  /**
   *  Repeats the observable sequence a specified number of times. If the repeat count is not specified, the sequence repeats indefinitely.
   * @param {Number} [repeatCount]  Number of times to repeat the sequence. If not provided, repeats the sequence indefinitely.
   * @returns {Observable} The observable sequence producing the elements of the given sequence repeatedly.
   */
  observableProto.repeat = function (repeatCount) {
    return enumerableRepeat(this, repeatCount).concat();
  };

  /**
   *  Repeats the source observable sequence the specified number of times or until it successfully terminates. If the retry count is not specified, it retries indefinitely.
   *  Note if you encounter an error and want it to retry once, then you must use .retry(2);
   *
   * @example
   *  var res = retried = retry.repeat();
   *  var res = retried = retry.repeat(2);
   * @param {Number} [retryCount]  Number of times to retry the sequence. If not provided, retry the sequence indefinitely.
   * @returns {Observable} An observable sequence producing the elements of the given sequence repeatedly until it terminates successfully.
   */
  observableProto.retry = function (retryCount) {
    return enumerableRepeat(this, retryCount).catchError();
  };

  /**
   *  Repeats the source observable sequence upon error each time the notifier emits or until it successfully terminates. 
   *  if the notifier completes, the observable sequence completes.
   *
   * @example
   *  var timer = Observable.timer(500);
   *  var source = observable.retryWhen(timer);
   * @param {Observable} [notifier] An observable that triggers the retries or completes the observable with onNext or onCompleted respectively.
   * @returns {Observable} An observable sequence producing the elements of the given sequence repeatedly until it terminates successfully.
   */
  observableProto.retryWhen = function (notifier) {
    return enumerableRepeat(this).catchErrorWhen(notifier);
  };
  var ScanObservable = (function(__super__) {
    inherits(ScanObservable, __super__);
    function ScanObservable(source, accumulator, hasSeed, seed) {
      this.source = source;
      this.accumulator = accumulator;
      this.hasSeed = hasSeed;
      this.seed = seed;
      __super__.call(this);
    }

    ScanObservable.prototype.subscribeCore = function(o) {
      return this.source.subscribe(new ScanObserver(o,this));
    };

    return ScanObservable;
  }(ObservableBase));

  var ScanObserver = (function (__super__) {
    inherits(ScanObserver, __super__);
    function ScanObserver(o, parent) {
      this._o = o;
      this._p = parent;
      this._fn = parent.accumulator;
      this._hs = parent.hasSeed;
      this._s = parent.seed;
      this._ha = false;
      this._a = null;
      this._hv = false;
      this._i = 0;
      __super__.call(this);
    }

    ScanObserver.prototype.next = function (x) {
      !this._hv && (this._hv = true);
      if (this._ha) {
        this._a = tryCatch(this._fn)(this._a, x, this._i, this._p);
      } else {
        this._a = this._hs ? tryCatch(this._fn)(this._s, x, this._i, this._p) : x;
        this._ha = true;
      }
      if (this._a === errorObj) { return this._o.onError(this._a.e); }
      this._o.onNext(this._a);
      this._i++;
    };

    ScanObserver.prototype.error = function (e) {
      this._o.onError(e);
    };

    ScanObserver.prototype.completed = function () {
      !this._hv && this._hs && this._o.onNext(this._s);
      this._o.onCompleted();
    };

    return ScanObserver;
  }(AbstractObserver));

  /**
  *  Applies an accumulator function over an observable sequence and returns each intermediate result. The optional seed value is used as the initial accumulator value.
  *  For aggregation behavior with no intermediate results, see Observable.aggregate.
  * @param {Mixed} [seed] The initial accumulator value.
  * @param {Function} accumulator An accumulator function to be invoked on each element.
  * @returns {Observable} An observable sequence containing the accumulated values.
  */
  observableProto.scan = function () {
    var hasSeed = false, seed, accumulator = arguments[0];
    if (arguments.length === 2) {
      hasSeed = true;
      seed = arguments[1];
    }
    return new ScanObservable(this, accumulator, hasSeed, seed);
  };

  var SkipLastObservable = (function (__super__) {
    inherits(SkipLastObservable, __super__);
    function SkipLastObservable(source, c) {
      this.source = source;
      this._c = c;
      __super__.call(this);
    }

    SkipLastObservable.prototype.subscribeCore = function (o) {
      return this.source.subscribe(new SkipLastObserver(o, this._c));
    };

    return SkipLastObservable;
  }(ObservableBase));

  var SkipLastObserver = (function (__super__) {
    inherits(SkipLastObserver, __super__);
    function SkipLastObserver(o, c) {
      this._o = o;
      this._c = c;
      this._q = [];
      __super__.call(this);
    }

    SkipLastObserver.prototype.next = function (x) {
      this._q.push(x);
      this._q.length > this._c && this._o.onNext(this._q.shift());
    };

    SkipLastObserver.prototype.error = function (e) {
      this._o.onError(e);
    };

    SkipLastObserver.prototype.completed = function () {
      this._o.onCompleted();
    };

    return SkipLastObserver;
  }(AbstractObserver));

  /**
   *  Bypasses a specified number of elements at the end of an observable sequence.
   * @description
   *  This operator accumulates a queue with a length enough to store the first `count` elements. As more elements are
   *  received, elements are taken from the front of the queue and produced on the result sequence. This causes elements to be delayed.
   * @param count Number of elements to bypass at the end of the source sequence.
   * @returns {Observable} An observable sequence containing the source sequence elements except for the bypassed ones at the end.
   */
  observableProto.skipLast = function (count) {
    if (count < 0) { throw new ArgumentOutOfRangeError(); }
    return new SkipLastObservable(this, count);
  };

  /**
   *  Prepends a sequence of values to an observable sequence with an optional scheduler and an argument list of values to prepend.
   *  @example
   *  var res = source.startWith(1, 2, 3);
   *  var res = source.startWith(Rx.Scheduler.timeout, 1, 2, 3);
   * @param {Arguments} args The specified values to prepend to the observable sequence
   * @returns {Observable} The source sequence prepended with the specified values.
   */
  observableProto.startWith = function () {
    var values, scheduler, start = 0;
    if (!!arguments.length && isScheduler(arguments[0])) {
      scheduler = arguments[0];
      start = 1;
    } else {
      scheduler = immediateScheduler;
    }
    for(var args = [], i = start, len = arguments.length; i < len; i++) { args.push(arguments[i]); }
    return enumerableOf([observableFromArray(args, scheduler), this]).concat();
  };

  var TakeLastObserver = (function (__super__) {
    inherits(TakeLastObserver, __super__);
    function TakeLastObserver(o, c) {
      this._o = o;
      this._c = c;
      this._q = [];
      __super__.call(this);
    }

    TakeLastObserver.prototype.next = function (x) {
      this._q.push(x);
      this._q.length > this._c && this._q.shift();
    };

    TakeLastObserver.prototype.error = function (e) {
      this._o.onError(e);
    };

    TakeLastObserver.prototype.completed = function () {
      while (this._q.length > 0) { this._o.onNext(this._q.shift()); }
      this._o.onCompleted();
    };

    return TakeLastObserver;
  }(AbstractObserver));

  /**
   *  Returns a specified number of contiguous elements from the end of an observable sequence.
   * @description
   *  This operator accumulates a buffer with a length enough to store elements count elements. Upon completion of
   *  the source sequence, this buffer is drained on the result sequence. This causes the elements to be delayed.
   * @param {Number} count Number of elements to take from the end of the source sequence.
   * @returns {Observable} An observable sequence containing the specified number of elements from the end of the source sequence.
   */
  observableProto.takeLast = function (count) {
    if (count < 0) { throw new ArgumentOutOfRangeError(); }
    var source = this;
    return new AnonymousObservable(function (o) {
      return source.subscribe(new TakeLastObserver(o, count));
    }, source);
  };

  var TakeLastBufferObserver = (function (__super__) {
    inherits(TakeLastBufferObserver, __super__);
    function TakeLastBufferObserver(o, c) {
      this._o = o;
      this._c = c;
      this._q = [];
      __super__.call(this);
    }

    TakeLastBufferObserver.prototype.next = function (x) {
      this._q.push(x);
      this._q.length > this._c && this._q.shift();
    };

    TakeLastBufferObserver.prototype.error = function (e) {
      this._o.onError(e);
    };

    TakeLastBufferObserver.prototype.completed = function () {
      this._o.onNext(this._q);
      this._o.onCompleted();
    };

    return TakeLastBufferObserver;
  }(AbstractObserver));

  /**
   *  Returns an array with the specified number of contiguous elements from the end of an observable sequence.
   *
   * @description
   *  This operator accumulates a buffer with a length enough to store count elements. Upon completion of the
   *  source sequence, this buffer is produced on the result sequence.
   * @param {Number} count Number of elements to take from the end of the source sequence.
   * @returns {Observable} An observable sequence containing a single array with the specified number of elements from the end of the source sequence.
   */
  observableProto.takeLastBuffer = function (count) {
    if (count < 0) { throw new ArgumentOutOfRangeError(); }
    var source = this;
    return new AnonymousObservable(function (o) {
      return source.subscribe(new TakeLastBufferObserver(o, count));
    }, source);
  };

  /**
   *  Projects each element of an observable sequence into zero or more windows which are produced based on element count information.
   * @param {Number} count Length of each window.
   * @param {Number} [skip] Number of elements to skip between creation of consecutive windows. If not specified, defaults to the count.
   * @returns {Observable} An observable sequence of windows.
   */
  observableProto.windowWithCount = function (count, skip) {
    var source = this;
    +count || (count = 0);
    Math.abs(count) === Infinity && (count = 0);
    if (count <= 0) { throw new ArgumentOutOfRangeError(); }
    skip == null && (skip = count);
    +skip || (skip = 0);
    Math.abs(skip) === Infinity && (skip = 0);

    if (skip <= 0) { throw new ArgumentOutOfRangeError(); }
    return new AnonymousObservable(function (observer) {
      var m = new SingleAssignmentDisposable(),
        refCountDisposable = new RefCountDisposable(m),
        n = 0,
        q = [];

      function createWindow () {
        var s = new Subject();
        q.push(s);
        observer.onNext(addRef(s, refCountDisposable));
      }

      createWindow();

      m.setDisposable(source.subscribe(
        function (x) {
          for (var i = 0, len = q.length; i < len; i++) { q[i].onNext(x); }
          var c = n - count + 1;
          c >= 0 && c % skip === 0 && q.shift().onCompleted();
          ++n % skip === 0 && createWindow();
        },
        function (e) {
          while (q.length > 0) { q.shift().onError(e); }
          observer.onError(e);
        },
        function () {
          while (q.length > 0) { q.shift().onCompleted(); }
          observer.onCompleted();
        }
      ));
      return refCountDisposable;
    }, source);
  };

observableProto.flatMapConcat = observableProto.concatMap = function(selector, resultSelector, thisArg) {
    return new FlatMapObservable(this, selector, resultSelector, thisArg).merge(1);
};
  /**
   * Projects each notification of an observable sequence to an observable sequence and concats the resulting observable sequences into one observable sequence.
   * @param {Function} onNext A transform function to apply to each element; the second parameter of the function represents the index of the source element.
   * @param {Function} onError A transform function to apply when an error occurs in the source sequence.
   * @param {Function} onCompleted A transform function to apply when the end of the source sequence is reached.
   * @param {Any} [thisArg] An optional "this" to use to invoke each transform.
   * @returns {Observable} An observable sequence whose elements are the result of invoking the one-to-many transform function corresponding to each notification in the input sequence.
   */
  observableProto.concatMapObserver = observableProto.selectConcatObserver = function(onNext, onError, onCompleted, thisArg) {
    var source = this,
        onNextFunc = bindCallback(onNext, thisArg, 2),
        onErrorFunc = bindCallback(onError, thisArg, 1),
        onCompletedFunc = bindCallback(onCompleted, thisArg, 0);
    return new AnonymousObservable(function (observer) {
      var index = 0;
      return source.subscribe(
        function (x) {
          var result;
          try {
            result = onNextFunc(x, index++);
          } catch (e) {
            observer.onError(e);
            return;
          }
          isPromise(result) && (result = observableFromPromise(result));
          observer.onNext(result);
        },
        function (err) {
          var result;
          try {
            result = onErrorFunc(err);
          } catch (e) {
            observer.onError(e);
            return;
          }
          isPromise(result) && (result = observableFromPromise(result));
          observer.onNext(result);
          observer.onCompleted();
        },
        function () {
          var result;
          try {
            result = onCompletedFunc();
          } catch (e) {
            observer.onError(e);
            return;
          }
          isPromise(result) && (result = observableFromPromise(result));
          observer.onNext(result);
          observer.onCompleted();
        });
    }, this).concatAll();
  };

  var DefaultIfEmptyObserver = (function (__super__) {
    inherits(DefaultIfEmptyObserver, __super__);
    function DefaultIfEmptyObserver(o, d) {
      this._o = o;
      this._d = d;
      this._f = false;
      __super__.call(this);
    }

    DefaultIfEmptyObserver.prototype.next = function (x) {
      this._f = true;
      this._o.onNext(x);
    };

    DefaultIfEmptyObserver.prototype.error = function (e) {
      this._o.onError(e);
    };

    DefaultIfEmptyObserver.prototype.completed = function () {
      !this._f && this._o.onNext(this._d);
      this._o.onCompleted();
    };

    return DefaultIfEmptyObserver;
  }(AbstractObserver));

  /**
   *  Returns the elements of the specified sequence or the specified value in a singleton sequence if the sequence is empty.
   *
   *  var res = obs = xs.defaultIfEmpty();
   *  2 - obs = xs.defaultIfEmpty(false);
   *
   * @memberOf Observable#
   * @param defaultValue The value to return if the sequence is empty. If not provided, this defaults to null.
   * @returns {Observable} An observable sequence that contains the specified default value if the source is empty; otherwise, the elements of the source itself.
   */
    observableProto.defaultIfEmpty = function (defaultValue) {
      var source = this;
      defaultValue === undefined && (defaultValue = null);
      return new AnonymousObservable(function (o) {
        return source.subscribe(new DefaultIfEmptyObserver(o, defaultValue));
      }, source);
    };

  // Swap out for Array.findIndex
  function arrayIndexOfComparer(array, item, comparer) {
    for (var i = 0, len = array.length; i < len; i++) {
      if (comparer(array[i], item)) { return i; }
    }
    return -1;
  }

  function HashSet(comparer) {
    this.comparer = comparer;
    this.set = [];
  }
  HashSet.prototype.push = function(value) {
    var retValue = arrayIndexOfComparer(this.set, value, this.comparer) === -1;
    retValue && this.set.push(value);
    return retValue;
  };

  var DistinctObservable = (function (__super__) {
    inherits(DistinctObservable, __super__);
    function DistinctObservable(source, keyFn, cmpFn) {
      this.source = source;
      this._keyFn = keyFn;
      this._cmpFn = cmpFn;
      __super__.call(this);
    }

    DistinctObservable.prototype.subscribeCore = function (o) {
      return this.source.subscribe(new DistinctObserver(o, this._keyFn, this._cmpFn));
    };

    return DistinctObservable;
  }(ObservableBase));

  var DistinctObserver = (function (__super__) {
    inherits(DistinctObserver, __super__);
    function DistinctObserver(o, keyFn, cmpFn) {
      this._o = o;
      this._keyFn = keyFn;
      this._h = new HashSet(cmpFn);
      __super__.call(this);
    }

    DistinctObserver.prototype.next = function (x) {
      var key = x;
      if (isFunction(this._keyFn)) {
        key = tryCatch(this._keyFn)(x);
        if (key === errorObj) { return this._o.onError(key.e); }
      }
      this._h.push(key) && this._o.onNext(x);
    };

    DistinctObserver.prototype.error = function (e) { this._o.onError(e); };
    DistinctObserver.prototype.completed = function () { this._o.onCompleted(); };

    return DistinctObserver;
  }(AbstractObserver));

  /**
   *  Returns an observable sequence that contains only distinct elements according to the keySelector and the comparer.
   *  Usage of this operator should be considered carefully due to the maintenance of an internal lookup structure which can grow large.
   *
   * @example
   *  var res = obs = xs.distinct();
   *  2 - obs = xs.distinct(function (x) { return x.id; });
   *  2 - obs = xs.distinct(function (x) { return x.id; }, function (a,b) { return a === b; });
   * @param {Function} [keySelector]  A function to compute the comparison key for each element.
   * @param {Function} [comparer]  Used to compare items in the collection.
   * @returns {Observable} An observable sequence only containing the distinct elements, based on a computed key value, from the source sequence.
   */
  observableProto.distinct = function (keySelector, comparer) {
    comparer || (comparer = defaultComparer);
    return new DistinctObservable(this, keySelector, comparer);
  };

  var MapObservable = (function (__super__) {
    inherits(MapObservable, __super__);

    function MapObservable(source, selector, thisArg) {
      this.source = source;
      this.selector = bindCallback(selector, thisArg, 3);
      __super__.call(this);
    }

    function innerMap(selector, self) {
      return function (x, i, o) { return selector.call(this, self.selector(x, i, o), i, o); };
    }

    MapObservable.prototype.internalMap = function (selector, thisArg) {
      return new MapObservable(this.source, innerMap(selector, this), thisArg);
    };

    MapObservable.prototype.subscribeCore = function (o) {
      return this.source.subscribe(new InnerObserver(o, this.selector, this));
    };

    inherits(InnerObserver, AbstractObserver);
    function InnerObserver(o, selector, source) {
      this.o = o;
      this.selector = selector;
      this.source = source;
      this.i = 0;
      AbstractObserver.call(this);
    }

    InnerObserver.prototype.next = function(x) {
      var result = tryCatch(this.selector)(x, this.i++, this.source);
      if (result === errorObj) { return this.o.onError(result.e); }
      this.o.onNext(result);
    };

    InnerObserver.prototype.error = function (e) {
      this.o.onError(e);
    };

    InnerObserver.prototype.completed = function () {
      this.o.onCompleted();
    };

    return MapObservable;

  }(ObservableBase));

  /**
  * Projects each element of an observable sequence into a new form by incorporating the element's index.
  * @param {Function} selector A transform function to apply to each source element; the second parameter of the function represents the index of the source element.
  * @param {Any} [thisArg] Object to use as this when executing callback.
  * @returns {Observable} An observable sequence whose elements are the result of invoking the transform function on each element of source.
  */
  observableProto.map = observableProto.select = function (selector, thisArg) {
    var selectorFn = typeof selector === 'function' ? selector : function () { return selector; };
    return this instanceof MapObservable ?
      this.internalMap(selectorFn, thisArg) :
      new MapObservable(this, selectorFn, thisArg);
  };

  function plucker(args, len) {
    return function mapper(x) {
      var currentProp = x;
      for (var i = 0; i < len; i++) {
        var p = currentProp[args[i]];
        if (typeof p !== 'undefined') {
          currentProp = p;
        } else {
          return undefined;
        }
      }
      return currentProp;
    }
  }

  /**
   * Retrieves the value of a specified nested property from all elements in
   * the Observable sequence.
   * @param {Arguments} arguments The nested properties to pluck.
   * @returns {Observable} Returns a new Observable sequence of property values.
   */
  observableProto.pluck = function () {
    var len = arguments.length, args = new Array(len);
    if (len === 0) { throw new Error('List of properties cannot be empty.'); }
    for(var i = 0; i < len; i++) { args[i] = arguments[i]; }
    return this.map(plucker(args, len));
  };

  /**
   * Projects each notification of an observable sequence to an observable sequence and merges the resulting observable sequences into one observable sequence.
   * @param {Function} onNext A transform function to apply to each element; the second parameter of the function represents the index of the source element.
   * @param {Function} onError A transform function to apply when an error occurs in the source sequence.
   * @param {Function} onCompleted A transform function to apply when the end of the source sequence is reached.
   * @param {Any} [thisArg] An optional "this" to use to invoke each transform.
   * @returns {Observable} An observable sequence whose elements are the result of invoking the one-to-many transform function corresponding to each notification in the input sequence.
   */
  observableProto.flatMapObserver = observableProto.selectManyObserver = function (onNext, onError, onCompleted, thisArg) {
    var source = this;
    return new AnonymousObservable(function (observer) {
      var index = 0;

      return source.subscribe(
        function (x) {
          var result;
          try {
            result = onNext.call(thisArg, x, index++);
          } catch (e) {
            observer.onError(e);
            return;
          }
          isPromise(result) && (result = observableFromPromise(result));
          observer.onNext(result);
        },
        function (err) {
          var result;
          try {
            result = onError.call(thisArg, err);
          } catch (e) {
            observer.onError(e);
            return;
          }
          isPromise(result) && (result = observableFromPromise(result));
          observer.onNext(result);
          observer.onCompleted();
        },
        function () {
          var result;
          try {
            result = onCompleted.call(thisArg);
          } catch (e) {
            observer.onError(e);
            return;
          }
          isPromise(result) && (result = observableFromPromise(result));
          observer.onNext(result);
          observer.onCompleted();
        });
    }, source).mergeAll();
  };

observableProto.flatMap = observableProto.selectMany = function(selector, resultSelector, thisArg) {
    return new FlatMapObservable(this, selector, resultSelector, thisArg).mergeAll();
};

Rx.Observable.prototype.flatMapLatest = function(selector, resultSelector, thisArg) {
    return new FlatMapObservable(this, selector, resultSelector, thisArg).switchLatest();
};
  var SkipObservable = (function(__super__) {
    inherits(SkipObservable, __super__);
    function SkipObservable(source, count) {
      this.source = source;
      this._count = count;
      __super__.call(this);
    }

    SkipObservable.prototype.subscribeCore = function (o) {
      return this.source.subscribe(new SkipObserver(o, this._count));
    };

    function SkipObserver(o, c) {
      this._o = o;
      this._r = c;
      AbstractObserver.call(this);
    }

    inherits(SkipObserver, AbstractObserver);

    SkipObserver.prototype.next = function (x) {
      if (this._r <= 0) {
        this._o.onNext(x);
      } else {
        this._r--;
      }
    };
    SkipObserver.prototype.error = function(e) { this._o.onError(e); };
    SkipObserver.prototype.completed = function() { this._o.onCompleted(); };

    return SkipObservable;
  }(ObservableBase));

  /**
   * Bypasses a specified number of elements in an observable sequence and then returns the remaining elements.
   * @param {Number} count The number of elements to skip before returning the remaining elements.
   * @returns {Observable} An observable sequence that contains the elements that occur after the specified index in the input sequence.
   */
  observableProto.skip = function (count) {
    if (count < 0) { throw new ArgumentOutOfRangeError(); }
    return new SkipObservable(this, count);
  };

  var SkipWhileObservable = (function (__super__) {
    inherits(SkipWhileObservable, __super__);
    function SkipWhileObservable(source, fn) {
      this.source = source;
      this._fn = fn;
      __super__.call(this);
    }

    SkipWhileObservable.prototype.subscribeCore = function (o) {
      return this.source.subscribe(new SkipWhileObserver(o, this));
    };

    return SkipWhileObservable;
  }(ObservableBase));

  var SkipWhileObserver = (function (__super__) {
    inherits(SkipWhileObserver, __super__);

    function SkipWhileObserver(o, p) {
      this._o = o;
      this._p = p;
      this._i = 0;
      this._r = false;
      __super__.call(this);
    }

    SkipWhileObserver.prototype.next = function (x) {
      if (!this._r) {
        var res = tryCatch(this._p._fn)(x, this._i++, this._p);
        if (res === errorObj) { return this._o.onError(res.e); }
        this._r = !res;
      }
      this._r && this._o.onNext(x);
    };
    SkipWhileObserver.prototype.error = function (e) { this._o.onError(e); };
    SkipWhileObserver.prototype.completed = function () { this._o.onCompleted(); };

    return SkipWhileObserver;
  }(AbstractObserver));

  /**
   *  Bypasses elements in an observable sequence as long as a specified condition is true and then returns the remaining elements.
   *  The element's index is used in the logic of the predicate function.
   *
   *  var res = source.skipWhile(function (value) { return value < 10; });
   *  var res = source.skipWhile(function (value, index) { return value < 10 || index < 10; });
   * @param {Function} predicate A function to test each element for a condition; the second parameter of the function represents the index of the source element.
   * @param {Any} [thisArg] Object to use as this when executing callback.
   * @returns {Observable} An observable sequence that contains the elements from the input sequence starting at the first element in the linear series that does not pass the test specified by predicate.
   */
  observableProto.skipWhile = function (predicate, thisArg) {
    var fn = bindCallback(predicate, thisArg, 3);
    return new SkipWhileObservable(this, fn);
  };

  var TakeObservable = (function(__super__) {
    inherits(TakeObservable, __super__);
    function TakeObservable(source, count) {
      this.source = source;
      this._count = count;
      __super__.call(this);
    }

    TakeObservable.prototype.subscribeCore = function (o) {
      return this.source.subscribe(new TakeObserver(o, this._count));
    };

    function TakeObserver(o, c) {
      this._o = o;
      this._c = c;
      this._r = c;
      AbstractObserver.call(this);
    }

    inherits(TakeObserver, AbstractObserver);

    TakeObserver.prototype.next = function (x) {
      if (this._r-- > 0) {
        this._o.onNext(x);
        this._r <= 0 && this._o.onCompleted();
      }
    };

    TakeObserver.prototype.error = function (e) { this._o.onError(e); };
    TakeObserver.prototype.completed = function () { this._o.onCompleted(); };

    return TakeObservable;
  }(ObservableBase));

  /**
   *  Returns a specified number of contiguous elements from the start of an observable sequence, using the specified scheduler for the edge case of take(0).
   * @param {Number} count The number of elements to return.
   * @param {Scheduler} [scheduler] Scheduler used to produce an OnCompleted message in case <paramref name="count count</paramref> is set to 0.
   * @returns {Observable} An observable sequence that contains the specified number of elements from the start of the input sequence.
   */
  observableProto.take = function (count, scheduler) {
    if (count < 0) { throw new ArgumentOutOfRangeError(); }
    if (count === 0) { return observableEmpty(scheduler); }
    return new TakeObservable(this, count);
  };

  var TakeWhileObservable = (function (__super__) {
    inherits(TakeWhileObservable, __super__);
    function TakeWhileObservable(source, fn) {
      this.source = source;
      this._fn = fn;
      __super__.call(this);
    }

    TakeWhileObservable.prototype.subscribeCore = function (o) {
      return this.source.subscribe(new TakeWhileObserver(o, this));
    };

    return TakeWhileObservable;
  }(ObservableBase));

  var TakeWhileObserver = (function (__super__) {
    inherits(TakeWhileObserver, __super__);

    function TakeWhileObserver(o, p) {
      this._o = o;
      this._p = p;
      this._i = 0;
      this._r = true;
      __super__.call(this);
    }

    TakeWhileObserver.prototype.next = function (x) {
      if (this._r) {
        this._r = tryCatch(this._p._fn)(x, this._i++, this._p);
        if (this._r === errorObj) { return this._o.onError(this._r.e); }
      }
      if (this._r) {
        this._o.onNext(x);
      } else {
        this._o.onCompleted();
      }
    };
    TakeWhileObserver.prototype.error = function (e) { this._o.onError(e); };
    TakeWhileObserver.prototype.completed = function () { this._o.onCompleted(); };

    return TakeWhileObserver;
  }(AbstractObserver));

  /**
   *  Returns elements from an observable sequence as long as a specified condition is true.
   *  The element's index is used in the logic of the predicate function.
   * @param {Function} predicate A function to test each element for a condition; the second parameter of the function represents the index of the source element.
   * @param {Any} [thisArg] Object to use as this when executing callback.
   * @returns {Observable} An observable sequence that contains the elements from the input sequence that occur before the element at which the test no longer passes.
   */
  observableProto.takeWhile = function (predicate, thisArg) {
    var fn = bindCallback(predicate, thisArg, 3);
    return new TakeWhileObservable(this, fn);
  };

  var FilterObservable = (function (__super__) {
    inherits(FilterObservable, __super__);

    function FilterObservable(source, predicate, thisArg) {
      this.source = source;
      this.predicate = bindCallback(predicate, thisArg, 3);
      __super__.call(this);
    }

    FilterObservable.prototype.subscribeCore = function (o) {
      return this.source.subscribe(new InnerObserver(o, this.predicate, this));
    };

    function innerPredicate(predicate, self) {
      return function(x, i, o) { return self.predicate(x, i, o) && predicate.call(this, x, i, o); }
    }

    FilterObservable.prototype.internalFilter = function(predicate, thisArg) {
      return new FilterObservable(this.source, innerPredicate(predicate, this), thisArg);
    };

    inherits(InnerObserver, AbstractObserver);
    function InnerObserver(o, predicate, source) {
      this.o = o;
      this.predicate = predicate;
      this.source = source;
      this.i = 0;
      AbstractObserver.call(this);
    }

    InnerObserver.prototype.next = function(x) {
      var shouldYield = tryCatch(this.predicate)(x, this.i++, this.source);
      if (shouldYield === errorObj) {
        return this.o.onError(shouldYield.e);
      }
      shouldYield && this.o.onNext(x);
    };

    InnerObserver.prototype.error = function (e) {
      this.o.onError(e);
    };

    InnerObserver.prototype.completed = function () {
      this.o.onCompleted();
    };

    return FilterObservable;

  }(ObservableBase));

  /**
  *  Filters the elements of an observable sequence based on a predicate by incorporating the element's index.
  * @param {Function} predicate A function to test each source element for a condition; the second parameter of the function represents the index of the source element.
  * @param {Any} [thisArg] Object to use as this when executing callback.
  * @returns {Observable} An observable sequence that contains elements from the input sequence that satisfy the condition.
  */
  observableProto.filter = observableProto.where = function (predicate, thisArg) {
    return this instanceof FilterObservable ? this.internalFilter(predicate, thisArg) :
      new FilterObservable(this, predicate, thisArg);
  };

  var TransduceObserver = (function (__super__) {
    inherits(TransduceObserver, __super__);
    function TransduceObserver(o, xform) {
      this._o = o;
      this._xform = xform;
      __super__.call(this);
    }

    TransduceObserver.prototype.next = function (x) {
      var res = tryCatch(this._xform['@@transducer/step']).call(this._xform, this._o, x);
      if (res === errorObj) { this._o.onError(res.e); }
    };

    TransduceObserver.prototype.error = function (e) { this._o.onError(e); };

    TransduceObserver.prototype.completed = function () {
      this._xform['@@transducer/result'](this._o);
    };

    return TransduceObserver;
  }(AbstractObserver));

  function transformForObserver(o) {
    return {
      '@@transducer/init': function() {
        return o;
      },
      '@@transducer/step': function(obs, input) {
        return obs.onNext(input);
      },
      '@@transducer/result': function(obs) {
        return obs.onCompleted();
      }
    };
  }

  /**
   * Executes a transducer to transform the observable sequence
   * @param {Transducer} transducer A transducer to execute
   * @returns {Observable} An Observable sequence containing the results from the transducer.
   */
  observableProto.transduce = function(transducer) {
    var source = this;
    return new AnonymousObservable(function(o) {
      var xform = transducer(transformForObserver(o));
      return source.subscribe(new TransduceObserver(o, xform));
    }, source);
  };

  var AnonymousObservable = Rx.AnonymousObservable = (function (__super__) {
    inherits(AnonymousObservable, __super__);

    // Fix subscriber to check for undefined or function returned to decorate as Disposable
    function fixSubscriber(subscriber) {
      return subscriber && isFunction(subscriber.dispose) ? subscriber :
        isFunction(subscriber) ? disposableCreate(subscriber) : disposableEmpty;
    }

    function setDisposable(s, state) {
      var ado = state[0], self = state[1];
      var sub = tryCatch(self.__subscribe).call(self, ado);
      if (sub === errorObj && !ado.fail(errorObj.e)) { thrower(errorObj.e); }
      ado.setDisposable(fixSubscriber(sub));
    }

    function AnonymousObservable(subscribe, parent) {
      this.source = parent;
      this.__subscribe = subscribe;
      __super__.call(this);
    }

    AnonymousObservable.prototype._subscribe = function (o) {
      var ado = new AutoDetachObserver(o), state = [ado, this];

      if (currentThreadScheduler.scheduleRequired()) {
        currentThreadScheduler.schedule(state, setDisposable);
      } else {
        setDisposable(null, state);
      }
      return ado;
    };

    return AnonymousObservable;

  }(Observable));

  var AutoDetachObserver = (function (__super__) {
    inherits(AutoDetachObserver, __super__);

    function AutoDetachObserver(observer) {
      __super__.call(this);
      this.observer = observer;
      this.m = new SingleAssignmentDisposable();
    }

    var AutoDetachObserverPrototype = AutoDetachObserver.prototype;

    AutoDetachObserverPrototype.next = function (value) {
      var result = tryCatch(this.observer.onNext).call(this.observer, value);
      if (result === errorObj) {
        this.dispose();
        thrower(result.e);
      }
    };

    AutoDetachObserverPrototype.error = function (err) {
      var result = tryCatch(this.observer.onError).call(this.observer, err);
      this.dispose();
      result === errorObj && thrower(result.e);
    };

    AutoDetachObserverPrototype.completed = function () {
      var result = tryCatch(this.observer.onCompleted).call(this.observer);
      this.dispose();
      result === errorObj && thrower(result.e);
    };

    AutoDetachObserverPrototype.setDisposable = function (value) { this.m.setDisposable(value); };
    AutoDetachObserverPrototype.getDisposable = function () { return this.m.getDisposable(); };

    AutoDetachObserverPrototype.dispose = function () {
      __super__.prototype.dispose.call(this);
      this.m.dispose();
    };

    return AutoDetachObserver;
  }(AbstractObserver));

  var InnerSubscription = function (s, o) {
    this._s = s;
    this._o = o;
  };

  InnerSubscription.prototype.dispose = function () {
    if (!this._s.isDisposed && this._o !== null) {
      var idx = this._s.observers.indexOf(this._o);
      this._s.observers.splice(idx, 1);
      this._o = null;
    }
  };

  /**
   *  Represents an object that is both an observable sequence as well as an observer.
   *  Each notification is broadcasted to all subscribed observers.
   */
  var Subject = Rx.Subject = (function (__super__) {
    inherits(Subject, __super__);
    function Subject() {
      __super__.call(this);
      this.isDisposed = false;
      this.isStopped = false;
      this.observers = [];
      this.hasError = false;
    }

    addProperties(Subject.prototype, Observer.prototype, {
      _subscribe: function (o) {
        checkDisposed(this);
        if (!this.isStopped) {
          this.observers.push(o);
          return new InnerSubscription(this, o);
        }
        if (this.hasError) {
          o.onError(this.error);
          return disposableEmpty;
        }
        o.onCompleted();
        return disposableEmpty;
      },
      /**
       * Indicates whether the subject has observers subscribed to it.
       * @returns {Boolean} Indicates whether the subject has observers subscribed to it.
       */
      hasObservers: function () { return this.observers.length > 0; },
      /**
       * Notifies all subscribed observers about the end of the sequence.
       */
      onCompleted: function () {
        checkDisposed(this);
        if (!this.isStopped) {
          this.isStopped = true;
          for (var i = 0, os = cloneArray(this.observers), len = os.length; i < len; i++) {
            os[i].onCompleted();
          }

          this.observers.length = 0;
        }
      },
      /**
       * Notifies all subscribed observers about the exception.
       * @param {Mixed} error The exception to send to all observers.
       */
      onError: function (error) {
        checkDisposed(this);
        if (!this.isStopped) {
          this.isStopped = true;
          this.error = error;
          this.hasError = true;
          for (var i = 0, os = cloneArray(this.observers), len = os.length; i < len; i++) {
            os[i].onError(error);
          }

          this.observers.length = 0;
        }
      },
      /**
       * Notifies all subscribed observers about the arrival of the specified element in the sequence.
       * @param {Mixed} value The value to send to all observers.
       */
      onNext: function (value) {
        checkDisposed(this);
        if (!this.isStopped) {
          for (var i = 0, os = cloneArray(this.observers), len = os.length; i < len; i++) {
            os[i].onNext(value);
          }
        }
      },
      /**
       * Unsubscribe all observers and release resources.
       */
      dispose: function () {
        this.isDisposed = true;
        this.observers = null;
      }
    });

    /**
     * Creates a subject from the specified observer and observable.
     * @param {Observer} observer The observer used to send messages to the subject.
     * @param {Observable} observable The observable used to subscribe to messages sent from the subject.
     * @returns {Subject} Subject implemented using the given observer and observable.
     */
    Subject.create = function (observer, observable) {
      return new AnonymousSubject(observer, observable);
    };

    return Subject;
  }(Observable));

  /**
   *  Represents the result of an asynchronous operation.
   *  The last value before the OnCompleted notification, or the error received through OnError, is sent to all subscribed observers.
   */
  var AsyncSubject = Rx.AsyncSubject = (function (__super__) {
    inherits(AsyncSubject, __super__);

    /**
     * Creates a subject that can only receive one value and that value is cached for all future observations.
     * @constructor
     */
    function AsyncSubject() {
      __super__.call(this);
      this.isDisposed = false;
      this.isStopped = false;
      this.hasValue = false;
      this.observers = [];
      this.hasError = false;
    }

    addProperties(AsyncSubject.prototype, Observer.prototype, {
      _subscribe: function (o) {
        checkDisposed(this);

        if (!this.isStopped) {
          this.observers.push(o);
          return new InnerSubscription(this, o);
        }

        if (this.hasError) {
          o.onError(this.error);
        } else if (this.hasValue) {
          o.onNext(this.value);
          o.onCompleted();
        } else {
          o.onCompleted();
        }

        return disposableEmpty;
      },
      /**
       * Indicates whether the subject has observers subscribed to it.
       * @returns {Boolean} Indicates whether the subject has observers subscribed to it.
       */
      hasObservers: function () {
        checkDisposed(this);
        return this.observers.length > 0;
      },
      /**
       * Notifies all subscribed observers about the end of the sequence, also causing the last received value to be sent out (if any).
       */
      onCompleted: function () {
        var i, len;
        checkDisposed(this);
        if (!this.isStopped) {
          this.isStopped = true;
          var os = cloneArray(this.observers), len = os.length;

          if (this.hasValue) {
            for (i = 0; i < len; i++) {
              var o = os[i];
              o.onNext(this.value);
              o.onCompleted();
            }
          } else {
            for (i = 0; i < len; i++) {
              os[i].onCompleted();
            }
          }

          this.observers.length = 0;
        }
      },
      /**
       * Notifies all subscribed observers about the error.
       * @param {Mixed} error The Error to send to all observers.
       */
      onError: function (error) {
        checkDisposed(this);
        if (!this.isStopped) {
          this.isStopped = true;
          this.hasError = true;
          this.error = error;

          for (var i = 0, os = cloneArray(this.observers), len = os.length; i < len; i++) {
            os[i].onError(error);
          }

          this.observers.length = 0;
        }
      },
      /**
       * Sends a value to the subject. The last value received before successful termination will be sent to all subscribed and future observers.
       * @param {Mixed} value The value to store in the subject.
       */
      onNext: function (value) {
        checkDisposed(this);
        if (this.isStopped) { return; }
        this.value = value;
        this.hasValue = true;
      },
      /**
       * Unsubscribe all observers and release resources.
       */
      dispose: function () {
        this.isDisposed = true;
        this.observers = null;
        this.error = null;
        this.value = null;
      }
    });

    return AsyncSubject;
  }(Observable));

  var AnonymousSubject = Rx.AnonymousSubject = (function (__super__) {
    inherits(AnonymousSubject, __super__);
    function AnonymousSubject(observer, observable) {
      this.observer = observer;
      this.observable = observable;
      __super__.call(this);
    }

    addProperties(AnonymousSubject.prototype, Observer.prototype, {
      _subscribe: function (o) {
        return this.observable.subscribe(o);
      },
      onCompleted: function () {
        this.observer.onCompleted();
      },
      onError: function (error) {
        this.observer.onError(error);
      },
      onNext: function (value) {
        this.observer.onNext(value);
      }
    });

    return AnonymousSubject;
  }(Observable));

  if (typeof define == 'function' && typeof define.amd == 'object' && define.amd) {
    root.Rx = Rx;

    define(function() {
      return Rx;
    });
  } else if (freeExports && freeModule) {
    // in Node.js or RingoJS
    if (moduleExports) {
      (freeModule.exports = Rx).Rx = Rx;
    } else {
      freeExports.Rx = Rx;
    }
  } else {
    // in a browser or Rhino
    root.Rx = Rx;
  }

  // All code before this point will be filtered from stack traces.
  var rEndingLine = captureLine();

}.call(this));