rx/dist/rx.core.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 () { },
  defaultNow = Rx.helpers.defaultNow = (function () { return !!Date.now ? Date.now : function () { return +new Date; }; }()),
  defaultError = Rx.helpers.defaultError = function (err) { throw err; },
  isPromise = Rx.helpers.isPromise = function (p) { return !!p && !isFunction(p.subscribe) && isFunction(p.then); },
  defaultSubComparer = Rx.helpers.defaultSubComparer = function (x, y) { return x > y ? 1 : (x < y ? -1 : 0); }
  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;
  }());

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

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

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

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

  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 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;
    }
  };

  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));

  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();

  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;

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

  /**
   *  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);
  };

  /**
   * 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 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 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 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 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));

  /**
   *  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);
  };

  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));