kefir/dist/kefir.esm.js

/*! Kefir.js v3.8.8
 *  https://github.com/kefirjs/kefir
 */

function createObj(proto) {
  var F = function () {};
  F.prototype = proto;
  return new F();
}

function extend(target /*, mixin1, mixin2...*/) {
  var length = arguments.length,
      i = void 0,
      prop = void 0;
  for (i = 1; i < length; i++) {
    for (prop in arguments[i]) {
      target[prop] = arguments[i][prop];
    }
  }
  return target;
}

function inherit(Child, Parent /*, mixin1, mixin2...*/) {
  var length = arguments.length,
      i = void 0;
  Child.prototype = createObj(Parent.prototype);
  Child.prototype.constructor = Child;
  for (i = 2; i < length; i++) {
    extend(Child.prototype, arguments[i]);
  }
  return Child;
}

var NOTHING = ['<nothing>'];
var END = 'end';
var VALUE = 'value';
var ERROR = 'error';
var ANY = 'any';

function concat(a, b) {
  var result = void 0,
      length = void 0,
      i = void 0,
      j = void 0;
  if (a.length === 0) {
    return b;
  }
  if (b.length === 0) {
    return a;
  }
  j = 0;
  result = new Array(a.length + b.length);
  length = a.length;
  for (i = 0; i < length; i++, j++) {
    result[j] = a[i];
  }
  length = b.length;
  for (i = 0; i < length; i++, j++) {
    result[j] = b[i];
  }
  return result;
}

function find(arr, value) {
  var length = arr.length,
      i = void 0;
  for (i = 0; i < length; i++) {
    if (arr[i] === value) {
      return i;
    }
  }
  return -1;
}

function findByPred(arr, pred) {
  var length = arr.length,
      i = void 0;
  for (i = 0; i < length; i++) {
    if (pred(arr[i])) {
      return i;
    }
  }
  return -1;
}

function cloneArray(input) {
  var length = input.length,
      result = new Array(length),
      i = void 0;
  for (i = 0; i < length; i++) {
    result[i] = input[i];
  }
  return result;
}

function remove(input, index) {
  var length = input.length,
      result = void 0,
      i = void 0,
      j = void 0;
  if (index >= 0 && index < length) {
    if (length === 1) {
      return [];
    } else {
      result = new Array(length - 1);
      for (i = 0, j = 0; i < length; i++) {
        if (i !== index) {
          result[j] = input[i];
          j++;
        }
      }
      return result;
    }
  } else {
    return input;
  }
}

function map(input, fn) {
  var length = input.length,
      result = new Array(length),
      i = void 0;
  for (i = 0; i < length; i++) {
    result[i] = fn(input[i]);
  }
  return result;
}

function forEach(arr, fn) {
  var length = arr.length,
      i = void 0;
  for (i = 0; i < length; i++) {
    fn(arr[i]);
  }
}

function fillArray(arr, value) {
  var length = arr.length,
      i = void 0;
  for (i = 0; i < length; i++) {
    arr[i] = value;
  }
}

function contains(arr, value) {
  return find(arr, value) !== -1;
}

function slide(cur, next, max) {
  var length = Math.min(max, cur.length + 1),
      offset = cur.length - length + 1,
      result = new Array(length),
      i = void 0;
  for (i = offset; i < length; i++) {
    result[i - offset] = cur[i];
  }
  result[length - 1] = next;
  return result;
}

function callSubscriber(type, fn, event) {
  if (type === ANY) {
    fn(event);
  } else if (type === event.type) {
    if (type === VALUE || type === ERROR) {
      fn(event.value);
    } else {
      fn();
    }
  }
}

function Dispatcher() {
  this._items = [];
  this._spies = [];
  this._inLoop = 0;
  this._removedItems = null;
}

extend(Dispatcher.prototype, {
  add: function (type, fn) {
    this._items = concat(this._items, [{ type: type, fn: fn }]);
    return this._items.length;
  },
  remove: function (type, fn) {
    var index = findByPred(this._items, function (x) {
      return x.type === type && x.fn === fn;
    });

    // if we're currently in a notification loop,
    // remember this subscriber was removed
    if (this._inLoop !== 0 && index !== -1) {
      if (this._removedItems === null) {
        this._removedItems = [];
      }
      this._removedItems.push(this._items[index]);
    }

    this._items = remove(this._items, index);
    return this._items.length;
  },
  addSpy: function (fn) {
    this._spies = concat(this._spies, [fn]);
    return this._spies.length;
  },


  // Because spies are only ever a function that perform logging as
  // their only side effect, we don't need the same complicated
  // removal logic like in remove()
  removeSpy: function (fn) {
    this._spies = remove(this._spies, this._spies.indexOf(fn));
    return this._spies.length;
  },
  dispatch: function (event) {
    this._inLoop++;
    for (var i = 0, spies = this._spies; this._spies !== null && i < spies.length; i++) {
      spies[i](event);
    }

    for (var _i = 0, items = this._items; _i < items.length; _i++) {
      // cleanup was called
      if (this._items === null) {
        break;
      }

      // this subscriber was removed
      if (this._removedItems !== null && contains(this._removedItems, items[_i])) {
        continue;
      }

      callSubscriber(items[_i].type, items[_i].fn, event);
    }
    this._inLoop--;
    if (this._inLoop === 0) {
      this._removedItems = null;
    }
  },
  cleanup: function () {
    this._items = null;
    this._spies = null;
  }
});

function Observable() {
  this._dispatcher = new Dispatcher();
  this._active = false;
  this._alive = true;
  this._activating = false;
  this._logHandlers = null;
  this._spyHandlers = null;
}

extend(Observable.prototype, {
  _name: 'observable',

  _onActivation: function () {},
  _onDeactivation: function () {},
  _setActive: function (active) {
    if (this._active !== active) {
      this._active = active;
      if (active) {
        this._activating = true;
        this._onActivation();
        this._activating = false;
      } else {
        this._onDeactivation();
      }
    }
  },
  _clear: function () {
    this._setActive(false);
    this._dispatcher.cleanup();
    this._dispatcher = null;
    this._logHandlers = null;
  },
  _emit: function (type, x) {
    switch (type) {
      case VALUE:
        return this._emitValue(x);
      case ERROR:
        return this._emitError(x);
      case END:
        return this._emitEnd();
    }
  },
  _emitValue: function (value) {
    if (this._alive) {
      this._dispatcher.dispatch({ type: VALUE, value: value });
    }
  },
  _emitError: function (value) {
    if (this._alive) {
      this._dispatcher.dispatch({ type: ERROR, value: value });
    }
  },
  _emitEnd: function () {
    if (this._alive) {
      this._alive = false;
      this._dispatcher.dispatch({ type: END });
      this._clear();
    }
  },
  _on: function (type, fn) {
    if (this._alive) {
      this._dispatcher.add(type, fn);
      this._setActive(true);
    } else {
      callSubscriber(type, fn, { type: END });
    }
    return this;
  },
  _off: function (type, fn) {
    if (this._alive) {
      var count = this._dispatcher.remove(type, fn);
      if (count === 0) {
        this._setActive(false);
      }
    }
    return this;
  },
  onValue: function (fn) {
    return this._on(VALUE, fn);
  },
  onError: function (fn) {
    return this._on(ERROR, fn);
  },
  onEnd: function (fn) {
    return this._on(END, fn);
  },
  onAny: function (fn) {
    return this._on(ANY, fn);
  },
  offValue: function (fn) {
    return this._off(VALUE, fn);
  },
  offError: function (fn) {
    return this._off(ERROR, fn);
  },
  offEnd: function (fn) {
    return this._off(END, fn);
  },
  offAny: function (fn) {
    return this._off(ANY, fn);
  },
  observe: function (observerOrOnValue, onError, onEnd) {
    var _this = this;
    var closed = false;

    var observer = !observerOrOnValue || typeof observerOrOnValue === 'function' ? { value: observerOrOnValue, error: onError, end: onEnd } : observerOrOnValue;

    var handler = function (event) {
      if (event.type === END) {
        closed = true;
      }
      if (event.type === VALUE && observer.value) {
        observer.value(event.value);
      } else if (event.type === ERROR && observer.error) {
        observer.error(event.value);
      } else if (event.type === END && observer.end) {
        observer.end(event.value);
      }
    };

    this.onAny(handler);

    return {
      unsubscribe: function () {
        if (!closed) {
          _this.offAny(handler);
          closed = true;
        }
      },

      get closed() {
        return closed;
      }
    };
  },


  // A and B must be subclasses of Stream and Property (order doesn't matter)
  _ofSameType: function (A, B) {
    return A.prototype.getType() === this.getType() ? A : B;
  },
  setName: function (sourceObs /* optional */, selfName) {
    this._name = selfName ? sourceObs._name + '.' + selfName : sourceObs;
    return this;
  },
  log: function () {
    var name = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : this.toString();

    var isCurrent = void 0;
    var handler = function (event) {
      var type = '<' + event.type + (isCurrent ? ':current' : '') + '>';
      if (event.type === END) {
        console.log(name, type);
      } else {
        console.log(name, type, event.value);
      }
    };

    if (this._alive) {
      if (!this._logHandlers) {
        this._logHandlers = [];
      }
      this._logHandlers.push({ name: name, handler: handler });
    }

    isCurrent = true;
    this.onAny(handler);
    isCurrent = false;

    return this;
  },
  offLog: function () {
    var name = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : this.toString();

    if (this._logHandlers) {
      var handlerIndex = findByPred(this._logHandlers, function (obj) {
        return obj.name === name;
      });
      if (handlerIndex !== -1) {
        this.offAny(this._logHandlers[handlerIndex].handler);
        this._logHandlers.splice(handlerIndex, 1);
      }
    }

    return this;
  },
  spy: function () {
    var name = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : this.toString();

    var handler = function (event) {
      var type = '<' + event.type + '>';
      if (event.type === END) {
        console.log(name, type);
      } else {
        console.log(name, type, event.value);
      }
    };
    if (this._alive) {
      if (!this._spyHandlers) {
        this._spyHandlers = [];
      }
      this._spyHandlers.push({ name: name, handler: handler });
      this._dispatcher.addSpy(handler);
    }
    return this;
  },
  offSpy: function () {
    var name = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : this.toString();

    if (this._spyHandlers) {
      var handlerIndex = findByPred(this._spyHandlers, function (obj) {
        return obj.name === name;
      });
      if (handlerIndex !== -1) {
        this._dispatcher.removeSpy(this._spyHandlers[handlerIndex].handler);
        this._spyHandlers.splice(handlerIndex, 1);
      }
    }
    return this;
  }
});

// extend() can't handle `toString` in IE8
Observable.prototype.toString = function () {
  return '[' + this._name + ']';
};

function Stream() {
  Observable.call(this);
}

inherit(Stream, Observable, {
  _name: 'stream',

  getType: function () {
    return 'stream';
  }
});

function Property() {
  Observable.call(this);
  this._currentEvent = null;
}

inherit(Property, Observable, {
  _name: 'property',

  _emitValue: function (value) {
    if (this._alive) {
      this._currentEvent = { type: VALUE, value: value };
      if (!this._activating) {
        this._dispatcher.dispatch({ type: VALUE, value: value });
      }
    }
  },
  _emitError: function (value) {
    if (this._alive) {
      this._currentEvent = { type: ERROR, value: value };
      if (!this._activating) {
        this._dispatcher.dispatch({ type: ERROR, value: value });
      }
    }
  },
  _emitEnd: function () {
    if (this._alive) {
      this._alive = false;
      if (!this._activating) {
        this._dispatcher.dispatch({ type: END });
      }
      this._clear();
    }
  },
  _on: function (type, fn) {
    if (this._alive) {
      this._dispatcher.add(type, fn);
      this._setActive(true);
    }
    if (this._currentEvent !== null) {
      callSubscriber(type, fn, this._currentEvent);
    }
    if (!this._alive) {
      callSubscriber(type, fn, { type: END });
    }
    return this;
  },
  getType: function () {
    return 'property';
  }
});

var neverS = new Stream();
neverS._emitEnd();
neverS._name = 'never';

function never() {
  return neverS;
}

function timeBased(mixin) {
  function AnonymousStream(wait, options) {
    var _this = this;

    Stream.call(this);
    this._wait = wait;
    this._intervalId = null;
    this._$onTick = function () {
      return _this._onTick();
    };
    this._init(options);
  }

  inherit(AnonymousStream, Stream, {
    _init: function () {},
    _free: function () {},
    _onTick: function () {},
    _onActivation: function () {
      this._intervalId = setInterval(this._$onTick, this._wait);
    },
    _onDeactivation: function () {
      if (this._intervalId !== null) {
        clearInterval(this._intervalId);
        this._intervalId = null;
      }
    },
    _clear: function () {
      Stream.prototype._clear.call(this);
      this._$onTick = null;
      this._free();
    }
  }, mixin);

  return AnonymousStream;
}

var S = timeBased({
  _name: 'later',

  _init: function (_ref) {
    var x = _ref.x;

    this._x = x;
  },
  _free: function () {
    this._x = null;
  },
  _onTick: function () {
    this._emitValue(this._x);
    this._emitEnd();
  }
});

function later(wait, x) {
  return new S(wait, { x: x });
}

var S$1 = timeBased({
  _name: 'interval',

  _init: function (_ref) {
    var x = _ref.x;

    this._x = x;
  },
  _free: function () {
    this._x = null;
  },
  _onTick: function () {
    this._emitValue(this._x);
  }
});

function interval(wait, x) {
  return new S$1(wait, { x: x });
}

var S$2 = timeBased({
  _name: 'sequentially',

  _init: function (_ref) {
    var xs = _ref.xs;

    this._xs = cloneArray(xs);
  },
  _free: function () {
    this._xs = null;
  },
  _onTick: function () {
    if (this._xs.length === 1) {
      this._emitValue(this._xs[0]);
      this._emitEnd();
    } else {
      this._emitValue(this._xs.shift());
    }
  }
});

function sequentially(wait, xs) {
  return xs.length === 0 ? never() : new S$2(wait, { xs: xs });
}

var S$3 = timeBased({
  _name: 'fromPoll',

  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
  },
  _free: function () {
    this._fn = null;
  },
  _onTick: function () {
    var fn = this._fn;
    this._emitValue(fn());
  }
});

function fromPoll(wait, fn) {
  return new S$3(wait, { fn: fn });
}

function emitter(obs) {
  function value(x) {
    obs._emitValue(x);
    return obs._active;
  }

  function error(x) {
    obs._emitError(x);
    return obs._active;
  }

  function end() {
    obs._emitEnd();
    return obs._active;
  }

  function event(e) {
    obs._emit(e.type, e.value);
    return obs._active;
  }

  return {
    value: value,
    error: error,
    end: end,
    event: event,

    // legacy
    emit: value,
    emitEvent: event
  };
}

var S$4 = timeBased({
  _name: 'withInterval',

  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
    this._emitter = emitter(this);
  },
  _free: function () {
    this._fn = null;
    this._emitter = null;
  },
  _onTick: function () {
    var fn = this._fn;
    fn(this._emitter);
  }
});

function withInterval(wait, fn) {
  return new S$4(wait, { fn: fn });
}

function S$5(fn) {
  Stream.call(this);
  this._fn = fn;
  this._unsubscribe = null;
}

inherit(S$5, Stream, {
  _name: 'stream',

  _onActivation: function () {
    var fn = this._fn;
    var unsubscribe = fn(emitter(this));
    this._unsubscribe = typeof unsubscribe === 'function' ? unsubscribe : null;

    // fix https://github.com/kefirjs/kefir/issues/35
    if (!this._active) {
      this._callUnsubscribe();
    }
  },
  _callUnsubscribe: function () {
    if (this._unsubscribe !== null) {
      this._unsubscribe();
      this._unsubscribe = null;
    }
  },
  _onDeactivation: function () {
    this._callUnsubscribe();
  },
  _clear: function () {
    Stream.prototype._clear.call(this);
    this._fn = null;
  }
});

function stream(fn) {
  return new S$5(fn);
}

function fromCallback(callbackConsumer) {
  var called = false;

  return stream(function (emitter) {
    if (!called) {
      callbackConsumer(function (x) {
        emitter.emit(x);
        emitter.end();
      });
      called = true;
    }
  }).setName('fromCallback');
}

function fromNodeCallback(callbackConsumer) {
  var called = false;

  return stream(function (emitter) {
    if (!called) {
      callbackConsumer(function (error, x) {
        if (error) {
          emitter.error(error);
        } else {
          emitter.emit(x);
        }
        emitter.end();
      });
      called = true;
    }
  }).setName('fromNodeCallback');
}

function spread(fn, length) {
  switch (length) {
    case 0:
      return function () {
        return fn();
      };
    case 1:
      return function (a) {
        return fn(a[0]);
      };
    case 2:
      return function (a) {
        return fn(a[0], a[1]);
      };
    case 3:
      return function (a) {
        return fn(a[0], a[1], a[2]);
      };
    case 4:
      return function (a) {
        return fn(a[0], a[1], a[2], a[3]);
      };
    default:
      return function (a) {
        return fn.apply(null, a);
      };
  }
}

function apply(fn, c, a) {
  var aLength = a ? a.length : 0;
  if (c == null) {
    switch (aLength) {
      case 0:
        return fn();
      case 1:
        return fn(a[0]);
      case 2:
        return fn(a[0], a[1]);
      case 3:
        return fn(a[0], a[1], a[2]);
      case 4:
        return fn(a[0], a[1], a[2], a[3]);
      default:
        return fn.apply(null, a);
    }
  } else {
    switch (aLength) {
      case 0:
        return fn.call(c);
      default:
        return fn.apply(c, a);
    }
  }
}

function fromSubUnsub(sub, unsub, transformer /* Function | falsey */) {
  return stream(function (emitter) {
    var handler = transformer ? function () {
      emitter.emit(apply(transformer, this, arguments));
    } : function (x) {
      emitter.emit(x);
    };

    sub(handler);
    return function () {
      return unsub(handler);
    };
  }).setName('fromSubUnsub');
}

var pairs = [['addEventListener', 'removeEventListener'], ['addListener', 'removeListener'], ['on', 'off']];

function fromEvents(target, eventName, transformer) {
  var sub = void 0,
      unsub = void 0;

  for (var i = 0; i < pairs.length; i++) {
    if (typeof target[pairs[i][0]] === 'function' && typeof target[pairs[i][1]] === 'function') {
      sub = pairs[i][0];
      unsub = pairs[i][1];
      break;
    }
  }

  if (sub === undefined) {
    throw new Error("target don't support any of " + 'addEventListener/removeEventListener, addListener/removeListener, on/off method pair');
  }

  return fromSubUnsub(function (handler) {
    return target[sub](eventName, handler);
  }, function (handler) {
    return target[unsub](eventName, handler);
  }, transformer).setName('fromEvents');
}

// HACK:
//   We don't call parent Class constructor, but instead putting all necessary
//   properties into prototype to simulate ended Property
//   (see Propperty and Observable classes).

function P(value) {
  this._currentEvent = { type: 'value', value: value, current: true };
}

inherit(P, Property, {
  _name: 'constant',
  _active: false,
  _activating: false,
  _alive: false,
  _dispatcher: null,
  _logHandlers: null
});

function constant(x) {
  return new P(x);
}

// HACK:
//   We don't call parent Class constructor, but instead putting all necessary
//   properties into prototype to simulate ended Property
//   (see Propperty and Observable classes).

function P$1(value) {
  this._currentEvent = { type: 'error', value: value, current: true };
}

inherit(P$1, Property, {
  _name: 'constantError',
  _active: false,
  _activating: false,
  _alive: false,
  _dispatcher: null,
  _logHandlers: null
});

function constantError(x) {
  return new P$1(x);
}

function createConstructor(BaseClass, name) {
  return function AnonymousObservable(source, options) {
    var _this = this;

    BaseClass.call(this);
    this._source = source;
    this._name = source._name + '.' + name;
    this._init(options);
    this._$handleAny = function (event) {
      return _this._handleAny(event);
    };
  };
}

function createClassMethods(BaseClass) {
  return {
    _init: function () {},
    _free: function () {},
    _handleValue: function (x) {
      this._emitValue(x);
    },
    _handleError: function (x) {
      this._emitError(x);
    },
    _handleEnd: function () {
      this._emitEnd();
    },
    _handleAny: function (event) {
      switch (event.type) {
        case VALUE:
          return this._handleValue(event.value);
        case ERROR:
          return this._handleError(event.value);
        case END:
          return this._handleEnd();
      }
    },
    _onActivation: function () {
      this._source.onAny(this._$handleAny);
    },
    _onDeactivation: function () {
      this._source.offAny(this._$handleAny);
    },
    _clear: function () {
      BaseClass.prototype._clear.call(this);
      this._source = null;
      this._$handleAny = null;
      this._free();
    }
  };
}

function createStream(name, mixin) {
  var S = createConstructor(Stream, name);
  inherit(S, Stream, createClassMethods(Stream), mixin);
  return S;
}

function createProperty(name, mixin) {
  var P = createConstructor(Property, name);
  inherit(P, Property, createClassMethods(Property), mixin);
  return P;
}

var P$2 = createProperty('toProperty', {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._getInitialCurrent = fn;
  },
  _onActivation: function () {
    if (this._getInitialCurrent !== null) {
      var getInitial = this._getInitialCurrent;
      this._emitValue(getInitial());
    }
    this._source.onAny(this._$handleAny); // copied from patterns/one-source
  }
});

function toProperty(obs) {
  var fn = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : null;

  if (fn !== null && typeof fn !== 'function') {
    throw new Error('You should call toProperty() with a function or no arguments.');
  }
  return new P$2(obs, { fn: fn });
}

var S$6 = createStream('changes', {
  _handleValue: function (x) {
    if (!this._activating) {
      this._emitValue(x);
    }
  },
  _handleError: function (x) {
    if (!this._activating) {
      this._emitError(x);
    }
  }
});

function changes(obs) {
  return new S$6(obs);
}

function fromPromise(promise) {
  var called = false;

  var result = stream(function (emitter) {
    if (!called) {
      var onValue = function (x) {
        emitter.emit(x);
        emitter.end();
      };
      var onError = function (x) {
        emitter.error(x);
        emitter.end();
      };
      var _promise = promise.then(onValue, onError);

      // prevent libraries like 'Q' or 'when' from swallowing exceptions
      if (_promise && typeof _promise.done === 'function') {
        _promise.done();
      }

      called = true;
    }
  });

  return toProperty(result, null).setName('fromPromise');
}

function getGlodalPromise() {
  if (typeof Promise === 'function') {
    return Promise;
  } else {
    throw new Error("There isn't default Promise, use shim or parameter");
  }
}

var toPromise = function (obs) {
  var Promise = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : getGlodalPromise();

  var last = null;
  return new Promise(function (resolve, reject) {
    obs.onAny(function (event) {
      if (event.type === END && last !== null) {
        (last.type === VALUE ? resolve : reject)(last.value);
        last = null;
      } else {
        last = event;
      }
    });
  });
};

function symbolObservablePonyfill(root) {
	var result;
	var Symbol = root.Symbol;

	if (typeof Symbol === 'function') {
		if (Symbol.observable) {
			result = Symbol.observable;
		} else {
			result = Symbol('observable');
			Symbol.observable = result;
		}
	} else {
		result = '@@observable';
	}

	return result;
}

/* global window */
var root;

if (typeof self !== 'undefined') {
  root = self;
} else if (typeof window !== 'undefined') {
  root = window;
} else if (typeof global !== 'undefined') {
  root = global;
} else if (typeof module !== 'undefined') {
  root = module;
} else {
  root = Function('return this')();
}

var result = symbolObservablePonyfill(root);

// this file contains some hot JS modules systems stuff

var $$observable = result.default ? result.default : result;

function fromESObservable(_observable) {
  var observable = _observable[$$observable] ? _observable[$$observable]() : _observable;
  return stream(function (emitter) {
    var unsub = observable.subscribe({
      error: function (error) {
        emitter.error(error);
        emitter.end();
      },
      next: function (value) {
        emitter.emit(value);
      },
      complete: function () {
        emitter.end();
      }
    });

    if (unsub.unsubscribe) {
      return function () {
        unsub.unsubscribe();
      };
    } else {
      return unsub;
    }
  }).setName('fromESObservable');
}

function ESObservable(observable) {
  this._observable = observable.takeErrors(1);
}

extend(ESObservable.prototype, {
  subscribe: function (observerOrOnNext, onError, onComplete) {
    var _this = this;

    var observer = typeof observerOrOnNext === 'function' ? { next: observerOrOnNext, error: onError, complete: onComplete } : observerOrOnNext;

    var fn = function (event) {
      if (event.type === END) {
        closed = true;
      }

      if (event.type === VALUE && observer.next) {
        observer.next(event.value);
      } else if (event.type === ERROR && observer.error) {
        observer.error(event.value);
      } else if (event.type === END && observer.complete) {
        observer.complete(event.value);
      }
    };

    this._observable.onAny(fn);
    var closed = false;

    var subscription = {
      unsubscribe: function () {
        closed = true;
        _this._observable.offAny(fn);
      },
      get closed() {
        return closed;
      }
    };
    return subscription;
  }
});

// Need to assign directly b/c Symbols aren't enumerable.
ESObservable.prototype[$$observable] = function () {
  return this;
};

function toESObservable() {
  return new ESObservable(this);
}

function collect(source, keys, values) {
  for (var prop in source) {
    if (source.hasOwnProperty(prop)) {
      keys.push(prop);
      values.push(source[prop]);
    }
  }
}

function defaultErrorsCombinator(errors) {
  var latestError = void 0;
  for (var i = 0; i < errors.length; i++) {
    if (errors[i] !== undefined) {
      if (latestError === undefined || latestError.index < errors[i].index) {
        latestError = errors[i];
      }
    }
  }
  return latestError.error;
}

function Combine(active, passive, combinator) {
  var _this = this;

  Stream.call(this);
  this._activeCount = active.length;
  this._sources = concat(active, passive);
  this._combinator = combinator;
  this._aliveCount = 0;
  this._latestValues = new Array(this._sources.length);
  this._latestErrors = new Array(this._sources.length);
  fillArray(this._latestValues, NOTHING);
  this._emitAfterActivation = false;
  this._endAfterActivation = false;
  this._latestErrorIndex = 0;

  this._$handlers = [];

  var _loop = function (i) {
    _this._$handlers.push(function (event) {
      return _this._handleAny(i, event);
    });
  };

  for (var i = 0; i < this._sources.length; i++) {
    _loop(i);
  }
}

inherit(Combine, Stream, {
  _name: 'combine',

  _onActivation: function () {
    this._aliveCount = this._activeCount;

    // we need to suscribe to _passive_ sources before _active_
    // (see https://github.com/kefirjs/kefir/issues/98)
    for (var i = this._activeCount; i < this._sources.length; i++) {
      this._sources[i].onAny(this._$handlers[i]);
    }
    for (var _i = 0; _i < this._activeCount; _i++) {
      this._sources[_i].onAny(this._$handlers[_i]);
    }

    if (this._emitAfterActivation) {
      this._emitAfterActivation = false;
      this._emitIfFull();
    }
    if (this._endAfterActivation) {
      this._emitEnd();
    }
  },
  _onDeactivation: function () {
    var length = this._sources.length,
        i = void 0;
    for (i = 0; i < length; i++) {
      this._sources[i].offAny(this._$handlers[i]);
    }
  },
  _emitIfFull: function () {
    var hasAllValues = true;
    var hasErrors = false;
    var length = this._latestValues.length;
    var valuesCopy = new Array(length);
    var errorsCopy = new Array(length);

    for (var i = 0; i < length; i++) {
      valuesCopy[i] = this._latestValues[i];
      errorsCopy[i] = this._latestErrors[i];

      if (valuesCopy[i] === NOTHING) {
        hasAllValues = false;
      }

      if (errorsCopy[i] !== undefined) {
        hasErrors = true;
      }
    }

    if (hasAllValues) {
      var combinator = this._combinator;
      this._emitValue(combinator(valuesCopy));
    }
    if (hasErrors) {
      this._emitError(defaultErrorsCombinator(errorsCopy));
    }
  },
  _handleAny: function (i, event) {
    if (event.type === VALUE || event.type === ERROR) {
      if (event.type === VALUE) {
        this._latestValues[i] = event.value;
        this._latestErrors[i] = undefined;
      }
      if (event.type === ERROR) {
        this._latestValues[i] = NOTHING;
        this._latestErrors[i] = {
          index: this._latestErrorIndex++,
          error: event.value
        };
      }

      if (i < this._activeCount) {
        if (this._activating) {
          this._emitAfterActivation = true;
        } else {
          this._emitIfFull();
        }
      }
    } else {
      // END

      if (i < this._activeCount) {
        this._aliveCount--;
        if (this._aliveCount === 0) {
          if (this._activating) {
            this._endAfterActivation = true;
          } else {
            this._emitEnd();
          }
        }
      }
    }
  },
  _clear: function () {
    Stream.prototype._clear.call(this);
    this._sources = null;
    this._latestValues = null;
    this._latestErrors = null;
    this._combinator = null;
    this._$handlers = null;
  }
});

function combineAsArray(active) {
  var passive = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : [];
  var combinator = arguments[2];

  if (!Array.isArray(passive)) {
    throw new Error('Combine can only combine active and passive collections of the same type.');
  }

  combinator = combinator ? spread(combinator, active.length + passive.length) : function (x) {
    return x;
  };
  return active.length === 0 ? never() : new Combine(active, passive, combinator);
}

function combineAsObject(active) {
  var passive = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
  var combinator = arguments[2];

  if (typeof passive !== 'object' || Array.isArray(passive)) {
    throw new Error('Combine can only combine active and passive collections of the same type.');
  }

  var keys = [],
      activeObservables = [],
      passiveObservables = [];

  collect(active, keys, activeObservables);
  collect(passive, keys, passiveObservables);

  var objectify = function (values) {
    var event = {};
    for (var i = values.length - 1; 0 <= i; i--) {
      event[keys[i]] = values[i];
    }
    return combinator ? combinator(event) : event;
  };

  return activeObservables.length === 0 ? never() : new Combine(activeObservables, passiveObservables, objectify);
}

function combine(active, passive, combinator) {
  if (typeof passive === 'function') {
    combinator = passive;
    passive = undefined;
  }

  return Array.isArray(active) ? combineAsArray(active, passive, combinator) : combineAsObject(active, passive, combinator);
}

var Observable$2 = {
  empty: function () {
    return never();
  },


  // Monoid based on merge() seems more useful than one based on concat().
  concat: function (a, b) {
    return a.merge(b);
  },
  of: function (x) {
    return constant(x);
  },
  map: function (fn, obs) {
    return obs.map(fn);
  },
  bimap: function (fnErr, fnVal, obs) {
    return obs.mapErrors(fnErr).map(fnVal);
  },


  // This ap strictly speaking incompatible with chain. If we derive ap from chain we get
  // different (not very useful) behavior. But spec requires that if method can be derived
  // it must have the same behavior as hand-written method. We intentionally violate the spec
  // in hope that it won't cause many troubles in practice. And in return we have more useful type.
  ap: function (obsFn, obsVal) {
    return combine([obsFn, obsVal], function (fn, val) {
      return fn(val);
    });
  },
  chain: function (fn, obs) {
    return obs.flatMap(fn);
  }
};



var staticLand = Object.freeze({
	Observable: Observable$2
});

var mixin = {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
  },
  _free: function () {
    this._fn = null;
  },
  _handleValue: function (x) {
    var fn = this._fn;
    this._emitValue(fn(x));
  }
};

var S$7 = createStream('map', mixin);
var P$3 = createProperty('map', mixin);

var id = function (x) {
  return x;
};

function map$1(obs) {
  var fn = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : id;

  return new (obs._ofSameType(S$7, P$3))(obs, { fn: fn });
}

var mixin$1 = {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
  },
  _free: function () {
    this._fn = null;
  },
  _handleValue: function (x) {
    var fn = this._fn;
    if (fn(x)) {
      this._emitValue(x);
    }
  }
};

var S$8 = createStream('filter', mixin$1);
var P$4 = createProperty('filter', mixin$1);

var id$1 = function (x) {
  return x;
};

function filter(obs) {
  var fn = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : id$1;

  return new (obs._ofSameType(S$8, P$4))(obs, { fn: fn });
}

var mixin$2 = {
  _init: function (_ref) {
    var n = _ref.n;

    this._n = n;
    if (n <= 0) {
      this._emitEnd();
    }
  },
  _handleValue: function (x) {
    if (this._n === 0) {
      return;
    }
    this._n--;
    this._emitValue(x);
    if (this._n === 0) {
      this._emitEnd();
    }
  }
};

var S$9 = createStream('take', mixin$2);
var P$5 = createProperty('take', mixin$2);

function take(obs, n) {
  return new (obs._ofSameType(S$9, P$5))(obs, { n: n });
}

var mixin$3 = {
  _init: function (_ref) {
    var n = _ref.n;

    this._n = n;
    if (n <= 0) {
      this._emitEnd();
    }
  },
  _handleError: function (x) {
    if (this._n === 0) {
      return;
    }
    this._n--;
    this._emitError(x);
    if (this._n === 0) {
      this._emitEnd();
    }
  }
};

var S$10 = createStream('takeErrors', mixin$3);
var P$6 = createProperty('takeErrors', mixin$3);

function takeErrors(obs, n) {
  return new (obs._ofSameType(S$10, P$6))(obs, { n: n });
}

var mixin$4 = {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
  },
  _free: function () {
    this._fn = null;
  },
  _handleValue: function (x) {
    var fn = this._fn;
    if (fn(x)) {
      this._emitValue(x);
    } else {
      this._emitEnd();
    }
  }
};

var S$11 = createStream('takeWhile', mixin$4);
var P$7 = createProperty('takeWhile', mixin$4);

var id$2 = function (x) {
  return x;
};

function takeWhile(obs) {
  var fn = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : id$2;

  return new (obs._ofSameType(S$11, P$7))(obs, { fn: fn });
}

var mixin$5 = {
  _init: function () {
    this._lastValue = NOTHING;
  },
  _free: function () {
    this._lastValue = null;
  },
  _handleValue: function (x) {
    this._lastValue = x;
  },
  _handleEnd: function () {
    if (this._lastValue !== NOTHING) {
      this._emitValue(this._lastValue);
    }
    this._emitEnd();
  }
};

var S$12 = createStream('last', mixin$5);
var P$8 = createProperty('last', mixin$5);

function last(obs) {
  return new (obs._ofSameType(S$12, P$8))(obs);
}

var mixin$6 = {
  _init: function (_ref) {
    var n = _ref.n;

    this._n = Math.max(0, n);
  },
  _handleValue: function (x) {
    if (this._n === 0) {
      this._emitValue(x);
    } else {
      this._n--;
    }
  }
};

var S$13 = createStream('skip', mixin$6);
var P$9 = createProperty('skip', mixin$6);

function skip(obs, n) {
  return new (obs._ofSameType(S$13, P$9))(obs, { n: n });
}

var mixin$7 = {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
  },
  _free: function () {
    this._fn = null;
  },
  _handleValue: function (x) {
    var fn = this._fn;
    if (this._fn !== null && !fn(x)) {
      this._fn = null;
    }
    if (this._fn === null) {
      this._emitValue(x);
    }
  }
};

var S$14 = createStream('skipWhile', mixin$7);
var P$10 = createProperty('skipWhile', mixin$7);

var id$3 = function (x) {
  return x;
};

function skipWhile(obs) {
  var fn = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : id$3;

  return new (obs._ofSameType(S$14, P$10))(obs, { fn: fn });
}

var mixin$8 = {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
    this._prev = NOTHING;
  },
  _free: function () {
    this._fn = null;
    this._prev = null;
  },
  _handleValue: function (x) {
    var fn = this._fn;
    if (this._prev === NOTHING || !fn(this._prev, x)) {
      this._prev = x;
      this._emitValue(x);
    }
  }
};

var S$15 = createStream('skipDuplicates', mixin$8);
var P$11 = createProperty('skipDuplicates', mixin$8);

var eq = function (a, b) {
  return a === b;
};

function skipDuplicates(obs) {
  var fn = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : eq;

  return new (obs._ofSameType(S$15, P$11))(obs, { fn: fn });
}

var mixin$9 = {
  _init: function (_ref) {
    var fn = _ref.fn,
        seed = _ref.seed;

    this._fn = fn;
    this._prev = seed;
  },
  _free: function () {
    this._prev = null;
    this._fn = null;
  },
  _handleValue: function (x) {
    if (this._prev !== NOTHING) {
      var fn = this._fn;
      this._emitValue(fn(this._prev, x));
    }
    this._prev = x;
  }
};

var S$16 = createStream('diff', mixin$9);
var P$12 = createProperty('diff', mixin$9);

function defaultFn(a, b) {
  return [a, b];
}

function diff(obs, fn) {
  var seed = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : NOTHING;

  return new (obs._ofSameType(S$16, P$12))(obs, { fn: fn || defaultFn, seed: seed });
}

var P$13 = createProperty('scan', {
  _init: function (_ref) {
    var fn = _ref.fn,
        seed = _ref.seed;

    this._fn = fn;
    this._seed = seed;
    if (seed !== NOTHING) {
      this._emitValue(seed);
    }
  },
  _free: function () {
    this._fn = null;
    this._seed = null;
  },
  _handleValue: function (x) {
    var fn = this._fn;
    if (this._currentEvent === null || this._currentEvent.type === ERROR) {
      this._emitValue(this._seed === NOTHING ? x : fn(this._seed, x));
    } else {
      this._emitValue(fn(this._currentEvent.value, x));
    }
  }
});

function scan(obs, fn) {
  var seed = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : NOTHING;

  return new P$13(obs, { fn: fn, seed: seed });
}

var mixin$10 = {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
  },
  _free: function () {
    this._fn = null;
  },
  _handleValue: function (x) {
    var fn = this._fn;
    var xs = fn(x);
    for (var i = 0; i < xs.length; i++) {
      this._emitValue(xs[i]);
    }
  }
};

var S$17 = createStream('flatten', mixin$10);

var id$4 = function (x) {
  return x;
};

function flatten(obs) {
  var fn = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : id$4;

  return new S$17(obs, { fn: fn });
}

var END_MARKER = {};

var mixin$11 = {
  _init: function (_ref) {
    var _this = this;

    var wait = _ref.wait;

    this._wait = Math.max(0, wait);
    this._buff = [];
    this._$shiftBuff = function () {
      var value = _this._buff.shift();
      if (value === END_MARKER) {
        _this._emitEnd();
      } else {
        _this._emitValue(value);
      }
    };
  },
  _free: function () {
    this._buff = null;
    this._$shiftBuff = null;
  },
  _handleValue: function (x) {
    if (this._activating) {
      this._emitValue(x);
    } else {
      this._buff.push(x);
      setTimeout(this._$shiftBuff, this._wait);
    }
  },
  _handleEnd: function () {
    if (this._activating) {
      this._emitEnd();
    } else {
      this._buff.push(END_MARKER);
      setTimeout(this._$shiftBuff, this._wait);
    }
  }
};

var S$18 = createStream('delay', mixin$11);
var P$14 = createProperty('delay', mixin$11);

function delay(obs, wait) {
  return new (obs._ofSameType(S$18, P$14))(obs, { wait: wait });
}

var now = Date.now ? function () {
  return Date.now();
} : function () {
  return new Date().getTime();
};

var mixin$12 = {
  _init: function (_ref) {
    var _this = this;

    var wait = _ref.wait,
        leading = _ref.leading,
        trailing = _ref.trailing;

    this._wait = Math.max(0, wait);
    this._leading = leading;
    this._trailing = trailing;
    this._trailingValue = null;
    this._timeoutId = null;
    this._endLater = false;
    this._lastCallTime = 0;
    this._$trailingCall = function () {
      return _this._trailingCall();
    };
  },
  _free: function () {
    this._trailingValue = null;
    this._$trailingCall = null;
  },
  _handleValue: function (x) {
    if (this._activating) {
      this._emitValue(x);
    } else {
      var curTime = now();
      if (this._lastCallTime === 0 && !this._leading) {
        this._lastCallTime = curTime;
      }
      var remaining = this._wait - (curTime - this._lastCallTime);
      if (remaining <= 0) {
        this._cancelTrailing();
        this._lastCallTime = curTime;
        this._emitValue(x);
      } else if (this._trailing) {
        this._cancelTrailing();
        this._trailingValue = x;
        this._timeoutId = setTimeout(this._$trailingCall, remaining);
      }
    }
  },
  _handleEnd: function () {
    if (this._activating) {
      this._emitEnd();
    } else {
      if (this._timeoutId) {
        this._endLater = true;
      } else {
        this._emitEnd();
      }
    }
  },
  _cancelTrailing: function () {
    if (this._timeoutId !== null) {
      clearTimeout(this._timeoutId);
      this._timeoutId = null;
    }
  },
  _trailingCall: function () {
    this._emitValue(this._trailingValue);
    this._timeoutId = null;
    this._trailingValue = null;
    this._lastCallTime = !this._leading ? 0 : now();
    if (this._endLater) {
      this._emitEnd();
    }
  }
};

var S$19 = createStream('throttle', mixin$12);
var P$15 = createProperty('throttle', mixin$12);

function throttle(obs, wait) {
  var _ref2 = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : {},
      _ref2$leading = _ref2.leading,
      leading = _ref2$leading === undefined ? true : _ref2$leading,
      _ref2$trailing = _ref2.trailing,
      trailing = _ref2$trailing === undefined ? true : _ref2$trailing;

  return new (obs._ofSameType(S$19, P$15))(obs, { wait: wait, leading: leading, trailing: trailing });
}

var mixin$13 = {
  _init: function (_ref) {
    var _this = this;

    var wait = _ref.wait,
        immediate = _ref.immediate;

    this._wait = Math.max(0, wait);
    this._immediate = immediate;
    this._lastAttempt = 0;
    this._timeoutId = null;
    this._laterValue = null;
    this._endLater = false;
    this._$later = function () {
      return _this._later();
    };
  },
  _free: function () {
    this._laterValue = null;
    this._$later = null;
  },
  _handleValue: function (x) {
    if (this._activating) {
      this._emitValue(x);
    } else {
      this._lastAttempt = now();
      if (this._immediate && !this._timeoutId) {
        this._emitValue(x);
      }
      if (!this._timeoutId) {
        this._timeoutId = setTimeout(this._$later, this._wait);
      }
      if (!this._immediate) {
        this._laterValue = x;
      }
    }
  },
  _handleEnd: function () {
    if (this._activating) {
      this._emitEnd();
    } else {
      if (this._timeoutId && !this._immediate) {
        this._endLater = true;
      } else {
        this._emitEnd();
      }
    }
  },
  _later: function () {
    var last = now() - this._lastAttempt;
    if (last < this._wait && last >= 0) {
      this._timeoutId = setTimeout(this._$later, this._wait - last);
    } else {
      this._timeoutId = null;
      if (!this._immediate) {
        var _laterValue = this._laterValue;
        this._laterValue = null;
        this._emitValue(_laterValue);
      }
      if (this._endLater) {
        this._emitEnd();
      }
    }
  }
};

var S$20 = createStream('debounce', mixin$13);
var P$16 = createProperty('debounce', mixin$13);

function debounce(obs, wait) {
  var _ref2 = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : {},
      _ref2$immediate = _ref2.immediate,
      immediate = _ref2$immediate === undefined ? false : _ref2$immediate;

  return new (obs._ofSameType(S$20, P$16))(obs, { wait: wait, immediate: immediate });
}

var mixin$14 = {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
  },
  _free: function () {
    this._fn = null;
  },
  _handleError: function (x) {
    var fn = this._fn;
    this._emitError(fn(x));
  }
};

var S$21 = createStream('mapErrors', mixin$14);
var P$17 = createProperty('mapErrors', mixin$14);

var id$5 = function (x) {
  return x;
};

function mapErrors(obs) {
  var fn = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : id$5;

  return new (obs._ofSameType(S$21, P$17))(obs, { fn: fn });
}

var mixin$15 = {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
  },
  _free: function () {
    this._fn = null;
  },
  _handleError: function (x) {
    var fn = this._fn;
    if (fn(x)) {
      this._emitError(x);
    }
  }
};

var S$22 = createStream('filterErrors', mixin$15);
var P$18 = createProperty('filterErrors', mixin$15);

var id$6 = function (x) {
  return x;
};

function filterErrors(obs) {
  var fn = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : id$6;

  return new (obs._ofSameType(S$22, P$18))(obs, { fn: fn });
}

var mixin$16 = {
  _handleValue: function () {}
};

var S$23 = createStream('ignoreValues', mixin$16);
var P$19 = createProperty('ignoreValues', mixin$16);

function ignoreValues(obs) {
  return new (obs._ofSameType(S$23, P$19))(obs);
}

var mixin$17 = {
  _handleError: function () {}
};

var S$24 = createStream('ignoreErrors', mixin$17);
var P$20 = createProperty('ignoreErrors', mixin$17);

function ignoreErrors(obs) {
  return new (obs._ofSameType(S$24, P$20))(obs);
}

var mixin$18 = {
  _handleEnd: function () {}
};

var S$25 = createStream('ignoreEnd', mixin$18);
var P$21 = createProperty('ignoreEnd', mixin$18);

function ignoreEnd(obs) {
  return new (obs._ofSameType(S$25, P$21))(obs);
}

var mixin$19 = {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
  },
  _free: function () {
    this._fn = null;
  },
  _handleEnd: function () {
    var fn = this._fn;
    this._emitValue(fn());
    this._emitEnd();
  }
};

var S$26 = createStream('beforeEnd', mixin$19);
var P$22 = createProperty('beforeEnd', mixin$19);

function beforeEnd(obs, fn) {
  return new (obs._ofSameType(S$26, P$22))(obs, { fn: fn });
}

var mixin$20 = {
  _init: function (_ref) {
    var min = _ref.min,
        max = _ref.max;

    this._max = max;
    this._min = min;
    this._buff = [];
  },
  _free: function () {
    this._buff = null;
  },
  _handleValue: function (x) {
    this._buff = slide(this._buff, x, this._max);
    if (this._buff.length >= this._min) {
      this._emitValue(this._buff);
    }
  }
};

var S$27 = createStream('slidingWindow', mixin$20);
var P$23 = createProperty('slidingWindow', mixin$20);

function slidingWindow(obs, max) {
  var min = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : 0;

  return new (obs._ofSameType(S$27, P$23))(obs, { min: min, max: max });
}

var mixin$21 = {
  _init: function (_ref) {
    var fn = _ref.fn,
        flushOnEnd = _ref.flushOnEnd;

    this._fn = fn;
    this._flushOnEnd = flushOnEnd;
    this._buff = [];
  },
  _free: function () {
    this._buff = null;
  },
  _flush: function () {
    if (this._buff !== null && this._buff.length !== 0) {
      this._emitValue(this._buff);
      this._buff = [];
    }
  },
  _handleValue: function (x) {
    this._buff.push(x);
    var fn = this._fn;
    if (!fn(x)) {
      this._flush();
    }
  },
  _handleEnd: function () {
    if (this._flushOnEnd) {
      this._flush();
    }
    this._emitEnd();
  }
};

var S$28 = createStream('bufferWhile', mixin$21);
var P$24 = createProperty('bufferWhile', mixin$21);

var id$7 = function (x) {
  return x;
};

function bufferWhile(obs, fn) {
  var _ref2 = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : {},
      _ref2$flushOnEnd = _ref2.flushOnEnd,
      flushOnEnd = _ref2$flushOnEnd === undefined ? true : _ref2$flushOnEnd;

  return new (obs._ofSameType(S$28, P$24))(obs, { fn: fn || id$7, flushOnEnd: flushOnEnd });
}

var mixin$22 = {
  _init: function (_ref) {
    var count = _ref.count,
        flushOnEnd = _ref.flushOnEnd;

    this._count = count;
    this._flushOnEnd = flushOnEnd;
    this._buff = [];
  },
  _free: function () {
    this._buff = null;
  },
  _flush: function () {
    if (this._buff !== null && this._buff.length !== 0) {
      this._emitValue(this._buff);
      this._buff = [];
    }
  },
  _handleValue: function (x) {
    this._buff.push(x);
    if (this._buff.length >= this._count) {
      this._flush();
    }
  },
  _handleEnd: function () {
    if (this._flushOnEnd) {
      this._flush();
    }
    this._emitEnd();
  }
};

var S$29 = createStream('bufferWithCount', mixin$22);
var P$25 = createProperty('bufferWithCount', mixin$22);

function bufferWhile$1(obs, count) {
  var _ref2 = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : {},
      _ref2$flushOnEnd = _ref2.flushOnEnd,
      flushOnEnd = _ref2$flushOnEnd === undefined ? true : _ref2$flushOnEnd;

  return new (obs._ofSameType(S$29, P$25))(obs, { count: count, flushOnEnd: flushOnEnd });
}

var mixin$23 = {
  _init: function (_ref) {
    var _this = this;

    var wait = _ref.wait,
        count = _ref.count,
        flushOnEnd = _ref.flushOnEnd;

    this._wait = wait;
    this._count = count;
    this._flushOnEnd = flushOnEnd;
    this._intervalId = null;
    this._$onTick = function () {
      return _this._flush();
    };
    this._buff = [];
  },
  _free: function () {
    this._$onTick = null;
    this._buff = null;
  },
  _flush: function () {
    if (this._buff !== null) {
      this._emitValue(this._buff);
      this._buff = [];
    }
  },
  _handleValue: function (x) {
    this._buff.push(x);
    if (this._buff.length >= this._count) {
      clearInterval(this._intervalId);
      this._flush();
      this._intervalId = setInterval(this._$onTick, this._wait);
    }
  },
  _handleEnd: function () {
    if (this._flushOnEnd && this._buff.length !== 0) {
      this._flush();
    }
    this._emitEnd();
  },
  _onActivation: function () {
    this._intervalId = setInterval(this._$onTick, this._wait);
    this._source.onAny(this._$handleAny); // copied from patterns/one-source
  },
  _onDeactivation: function () {
    if (this._intervalId !== null) {
      clearInterval(this._intervalId);
      this._intervalId = null;
    }
    this._source.offAny(this._$handleAny); // copied from patterns/one-source
  }
};

var S$30 = createStream('bufferWithTimeOrCount', mixin$23);
var P$26 = createProperty('bufferWithTimeOrCount', mixin$23);

function bufferWithTimeOrCount(obs, wait, count) {
  var _ref2 = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : {},
      _ref2$flushOnEnd = _ref2.flushOnEnd,
      flushOnEnd = _ref2$flushOnEnd === undefined ? true : _ref2$flushOnEnd;

  return new (obs._ofSameType(S$30, P$26))(obs, { wait: wait, count: count, flushOnEnd: flushOnEnd });
}

function xformForObs(obs) {
  return {
    '@@transducer/step': function (res, input) {
      obs._emitValue(input);
      return null;
    },
    '@@transducer/result': function () {
      obs._emitEnd();
      return null;
    }
  };
}

var mixin$24 = {
  _init: function (_ref) {
    var transducer = _ref.transducer;

    this._xform = transducer(xformForObs(this));
  },
  _free: function () {
    this._xform = null;
  },
  _handleValue: function (x) {
    if (this._xform['@@transducer/step'](null, x) !== null) {
      this._xform['@@transducer/result'](null);
    }
  },
  _handleEnd: function () {
    this._xform['@@transducer/result'](null);
  }
};

var S$31 = createStream('transduce', mixin$24);
var P$27 = createProperty('transduce', mixin$24);

function transduce(obs, transducer) {
  return new (obs._ofSameType(S$31, P$27))(obs, { transducer: transducer });
}

var mixin$25 = {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._handler = fn;
    this._emitter = emitter(this);
  },
  _free: function () {
    this._handler = null;
    this._emitter = null;
  },
  _handleAny: function (event) {
    this._handler(this._emitter, event);
  }
};

var S$32 = createStream('withHandler', mixin$25);
var P$28 = createProperty('withHandler', mixin$25);

function withHandler(obs, fn) {
  return new (obs._ofSameType(S$32, P$28))(obs, { fn: fn });
}

var isArray = Array.isArray || function (xs) {
  return Object.prototype.toString.call(xs) === '[object Array]';
};

function Zip(sources, combinator) {
  var _this = this;

  Stream.call(this);

  this._buffers = map(sources, function (source) {
    return isArray(source) ? cloneArray(source) : [];
  });
  this._sources = map(sources, function (source) {
    return isArray(source) ? never() : source;
  });

  this._combinator = combinator ? spread(combinator, this._sources.length) : function (x) {
    return x;
  };
  this._aliveCount = 0;

  this._$handlers = [];

  var _loop = function (i) {
    _this._$handlers.push(function (event) {
      return _this._handleAny(i, event);
    });
  };

  for (var i = 0; i < this._sources.length; i++) {
    _loop(i);
  }
}

inherit(Zip, Stream, {
  _name: 'zip',

  _onActivation: function () {
    // if all sources are arrays
    while (this._isFull()) {
      this._emit();
    }

    var length = this._sources.length;
    this._aliveCount = length;
    for (var i = 0; i < length && this._active; i++) {
      this._sources[i].onAny(this._$handlers[i]);
    }
  },
  _onDeactivation: function () {
    for (var i = 0; i < this._sources.length; i++) {
      this._sources[i].offAny(this._$handlers[i]);
    }
  },
  _emit: function () {
    var values = new Array(this._buffers.length);
    for (var i = 0; i < this._buffers.length; i++) {
      values[i] = this._buffers[i].shift();
    }
    var combinator = this._combinator;
    this._emitValue(combinator(values));
  },
  _isFull: function () {
    for (var i = 0; i < this._buffers.length; i++) {
      if (this._buffers[i].length === 0) {
        return false;
      }
    }
    return true;
  },
  _handleAny: function (i, event) {
    if (event.type === VALUE) {
      this._buffers[i].push(event.value);
      if (this._isFull()) {
        this._emit();
      }
    }
    if (event.type === ERROR) {
      this._emitError(event.value);
    }
    if (event.type === END) {
      this._aliveCount--;
      if (this._aliveCount === 0) {
        this._emitEnd();
      }
    }
  },
  _clear: function () {
    Stream.prototype._clear.call(this);
    this._sources = null;
    this._buffers = null;
    this._combinator = null;
    this._$handlers = null;
  }
});

function zip(observables, combinator /* Function | falsey */) {
  return observables.length === 0 ? never() : new Zip(observables, combinator);
}

var id$8 = function (x) {
  return x;
};

function AbstractPool() {
  var _this = this;

  var _ref = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {},
      _ref$queueLim = _ref.queueLim,
      queueLim = _ref$queueLim === undefined ? 0 : _ref$queueLim,
      _ref$concurLim = _ref.concurLim,
      concurLim = _ref$concurLim === undefined ? -1 : _ref$concurLim,
      _ref$drop = _ref.drop,
      drop = _ref$drop === undefined ? 'new' : _ref$drop;

  Stream.call(this);

  this._queueLim = queueLim < 0 ? -1 : queueLim;
  this._concurLim = concurLim < 0 ? -1 : concurLim;
  this._drop = drop;
  this._queue = [];
  this._curSources = [];
  this._$handleSubAny = function (event) {
    return _this._handleSubAny(event);
  };
  this._$endHandlers = [];
  this._currentlyAdding = null;

  if (this._concurLim === 0) {
    this._emitEnd();
  }
}

inherit(AbstractPool, Stream, {
  _name: 'abstractPool',

  _add: function (obj, toObs /* Function | falsey */) {
    toObs = toObs || id$8;
    if (this._concurLim === -1 || this._curSources.length < this._concurLim) {
      this._addToCur(toObs(obj));
    } else {
      if (this._queueLim === -1 || this._queue.length < this._queueLim) {
        this._addToQueue(toObs(obj));
      } else if (this._drop === 'old') {
        this._removeOldest();
        this._add(obj, toObs);
      }
    }
  },
  _addAll: function (obss) {
    var _this2 = this;

    forEach(obss, function (obs) {
      return _this2._add(obs);
    });
  },
  _remove: function (obs) {
    if (this._removeCur(obs) === -1) {
      this._removeQueue(obs);
    }
  },
  _addToQueue: function (obs) {
    this._queue = concat(this._queue, [obs]);
  },
  _addToCur: function (obs) {
    if (this._active) {
      // HACK:
      //
      // We have two optimizations for cases when `obs` is ended. We don't want
      // to add such observable to the list, but only want to emit events
      // from it (if it has some).
      //
      // Instead of this hacks, we could just did following,
      // but it would be 5-8 times slower:
      //
      //     this._curSources = concat(this._curSources, [obs]);
      //     this._subscribe(obs);
      //

      // #1
      // This one for cases when `obs` already ended
      // e.g., Kefir.constant() or Kefir.never()
      if (!obs._alive) {
        if (obs._currentEvent) {
          this._emit(obs._currentEvent.type, obs._currentEvent.value);
        }
        // The _emit above could have caused this stream to end.
        if (this._active) {
          if (this._queue.length !== 0) {
            this._pullQueue();
          } else if (this._curSources.length === 0) {
            this._onEmpty();
          }
        }
        return;
      }

      // #2
      // This one is for cases when `obs` going to end synchronously on
      // first subscriber e.g., Kefir.stream(em => {em.emit(1); em.end()})
      this._currentlyAdding = obs;
      obs.onAny(this._$handleSubAny);
      this._currentlyAdding = null;
      if (obs._alive) {
        this._curSources = concat(this._curSources, [obs]);
        if (this._active) {
          this._subToEnd(obs);
        }
      } else {
        if (this._queue.length !== 0) {
          this._pullQueue();
        } else if (this._curSources.length === 0) {
          this._onEmpty();
        }
      }
    } else {
      this._curSources = concat(this._curSources, [obs]);
    }
  },
  _subToEnd: function (obs) {
    var _this3 = this;

    var onEnd = function () {
      return _this3._removeCur(obs);
    };
    this._$endHandlers.push({ obs: obs, handler: onEnd });
    obs.onEnd(onEnd);
  },
  _subscribe: function (obs) {
    obs.onAny(this._$handleSubAny);

    // it can become inactive in responce of subscribing to `obs.onAny` above
    if (this._active) {
      this._subToEnd(obs);
    }
  },
  _unsubscribe: function (obs) {
    obs.offAny(this._$handleSubAny);

    var onEndI = findByPred(this._$endHandlers, function (obj) {
      return obj.obs === obs;
    });
    if (onEndI !== -1) {
      obs.offEnd(this._$endHandlers[onEndI].handler);
      this._$endHandlers.splice(onEndI, 1);
    }
  },
  _handleSubAny: function (event) {
    if (event.type === VALUE) {
      this._emitValue(event.value);
    } else if (event.type === ERROR) {
      this._emitError(event.value);
    }
  },
  _removeQueue: function (obs) {
    var index = find(this._queue, obs);
    this._queue = remove(this._queue, index);
    return index;
  },
  _removeCur: function (obs) {
    if (this._active) {
      this._unsubscribe(obs);
    }
    var index = find(this._curSources, obs);
    this._curSources = remove(this._curSources, index);
    if (index !== -1) {
      if (this._queue.length !== 0) {
        this._pullQueue();
      } else if (this._curSources.length === 0) {
        this._onEmpty();
      }
    }
    return index;
  },
  _removeOldest: function () {
    this._removeCur(this._curSources[0]);
  },
  _pullQueue: function () {
    if (this._queue.length !== 0) {
      this._queue = cloneArray(this._queue);
      this._addToCur(this._queue.shift());
    }
  },
  _onActivation: function () {
    for (var i = 0, sources = this._curSources; i < sources.length && this._active; i++) {
      this._subscribe(sources[i]);
    }
  },
  _onDeactivation: function () {
    for (var i = 0, sources = this._curSources; i < sources.length; i++) {
      this._unsubscribe(sources[i]);
    }
    if (this._currentlyAdding !== null) {
      this._unsubscribe(this._currentlyAdding);
    }
  },
  _isEmpty: function () {
    return this._curSources.length === 0;
  },
  _onEmpty: function () {},
  _clear: function () {
    Stream.prototype._clear.call(this);
    this._queue = null;
    this._curSources = null;
    this._$handleSubAny = null;
    this._$endHandlers = null;
  }
});

function Merge(sources) {
  AbstractPool.call(this);
  this._addAll(sources);
  this._initialised = true;
}

inherit(Merge, AbstractPool, {
  _name: 'merge',

  _onEmpty: function () {
    if (this._initialised) {
      this._emitEnd();
    }
  }
});

function merge(observables) {
  return observables.length === 0 ? never() : new Merge(observables);
}

function S$33(generator) {
  var _this = this;

  Stream.call(this);
  this._generator = generator;
  this._source = null;
  this._inLoop = false;
  this._iteration = 0;
  this._$handleAny = function (event) {
    return _this._handleAny(event);
  };
}

inherit(S$33, Stream, {
  _name: 'repeat',

  _handleAny: function (event) {
    if (event.type === END) {
      this._source = null;
      this._getSource();
    } else {
      this._emit(event.type, event.value);
    }
  },
  _getSource: function () {
    if (!this._inLoop) {
      this._inLoop = true;
      var generator = this._generator;
      while (this._source === null && this._alive && this._active) {
        this._source = generator(this._iteration++);
        if (this._source) {
          this._source.onAny(this._$handleAny);
        } else {
          this._emitEnd();
        }
      }
      this._inLoop = false;
    }
  },
  _onActivation: function () {
    if (this._source) {
      this._source.onAny(this._$handleAny);
    } else {
      this._getSource();
    }
  },
  _onDeactivation: function () {
    if (this._source) {
      this._source.offAny(this._$handleAny);
    }
  },
  _clear: function () {
    Stream.prototype._clear.call(this);
    this._generator = null;
    this._source = null;
    this._$handleAny = null;
  }
});

var repeat = function (generator) {
  return new S$33(generator);
};

function concat$1(observables) {
  return repeat(function (index) {
    return observables.length > index ? observables[index] : false;
  }).setName('concat');
}

function Pool() {
  AbstractPool.call(this);
}

inherit(Pool, AbstractPool, {
  _name: 'pool',

  plug: function (obs) {
    this._add(obs);
    return this;
  },
  unplug: function (obs) {
    this._remove(obs);
    return this;
  }
});

function FlatMap(source, fn, options) {
  var _this = this;

  AbstractPool.call(this, options);
  this._source = source;
  this._fn = fn;
  this._mainEnded = false;
  this._lastCurrent = null;
  this._$handleMain = function (event) {
    return _this._handleMain(event);
  };
}

inherit(FlatMap, AbstractPool, {
  _onActivation: function () {
    AbstractPool.prototype._onActivation.call(this);
    if (this._active) {
      this._source.onAny(this._$handleMain);
    }
  },
  _onDeactivation: function () {
    AbstractPool.prototype._onDeactivation.call(this);
    this._source.offAny(this._$handleMain);
    this._hadNoEvSinceDeact = true;
  },
  _handleMain: function (event) {
    if (event.type === VALUE) {
      // Is latest value before deactivation survived, and now is 'current' on this activation?
      // We don't want to handle such values, to prevent to constantly add
      // same observale on each activation/deactivation when our main source
      // is a `Kefir.conatant()` for example.
      var sameCurr = this._activating && this._hadNoEvSinceDeact && this._lastCurrent === event.value;
      if (!sameCurr) {
        this._add(event.value, this._fn);
      }
      this._lastCurrent = event.value;
      this._hadNoEvSinceDeact = false;
    }

    if (event.type === ERROR) {
      this._emitError(event.value);
    }

    if (event.type === END) {
      if (this._isEmpty()) {
        this._emitEnd();
      } else {
        this._mainEnded = true;
      }
    }
  },
  _onEmpty: function () {
    if (this._mainEnded) {
      this._emitEnd();
    }
  },
  _clear: function () {
    AbstractPool.prototype._clear.call(this);
    this._source = null;
    this._lastCurrent = null;
    this._$handleMain = null;
  }
});

function FlatMapErrors(source, fn) {
  FlatMap.call(this, source, fn);
}

inherit(FlatMapErrors, FlatMap, {
  // Same as in FlatMap, only VALUE/ERROR flipped
  _handleMain: function (event) {
    if (event.type === ERROR) {
      var sameCurr = this._activating && this._hadNoEvSinceDeact && this._lastCurrent === event.value;
      if (!sameCurr) {
        this._add(event.value, this._fn);
      }
      this._lastCurrent = event.value;
      this._hadNoEvSinceDeact = false;
    }

    if (event.type === VALUE) {
      this._emitValue(event.value);
    }

    if (event.type === END) {
      if (this._isEmpty()) {
        this._emitEnd();
      } else {
        this._mainEnded = true;
      }
    }
  }
});

function createConstructor$1(BaseClass, name) {
  return function AnonymousObservable(primary, secondary, options) {
    var _this = this;

    BaseClass.call(this);
    this._primary = primary;
    this._secondary = secondary;
    this._name = primary._name + '.' + name;
    this._lastSecondary = NOTHING;
    this._$handleSecondaryAny = function (event) {
      return _this._handleSecondaryAny(event);
    };
    this._$handlePrimaryAny = function (event) {
      return _this._handlePrimaryAny(event);
    };
    this._init(options);
  };
}

function createClassMethods$1(BaseClass) {
  return {
    _init: function () {},
    _free: function () {},
    _handlePrimaryValue: function (x) {
      this._emitValue(x);
    },
    _handlePrimaryError: function (x) {
      this._emitError(x);
    },
    _handlePrimaryEnd: function () {
      this._emitEnd();
    },
    _handleSecondaryValue: function (x) {
      this._lastSecondary = x;
    },
    _handleSecondaryError: function (x) {
      this._emitError(x);
    },
    _handleSecondaryEnd: function () {},
    _handlePrimaryAny: function (event) {
      switch (event.type) {
        case VALUE:
          return this._handlePrimaryValue(event.value);
        case ERROR:
          return this._handlePrimaryError(event.value);
        case END:
          return this._handlePrimaryEnd(event.value);
      }
    },
    _handleSecondaryAny: function (event) {
      switch (event.type) {
        case VALUE:
          return this._handleSecondaryValue(event.value);
        case ERROR:
          return this._handleSecondaryError(event.value);
        case END:
          this._handleSecondaryEnd(event.value);
          this._removeSecondary();
      }
    },
    _removeSecondary: function () {
      if (this._secondary !== null) {
        this._secondary.offAny(this._$handleSecondaryAny);
        this._$handleSecondaryAny = null;
        this._secondary = null;
      }
    },
    _onActivation: function () {
      if (this._secondary !== null) {
        this._secondary.onAny(this._$handleSecondaryAny);
      }
      if (this._active) {
        this._primary.onAny(this._$handlePrimaryAny);
      }
    },
    _onDeactivation: function () {
      if (this._secondary !== null) {
        this._secondary.offAny(this._$handleSecondaryAny);
      }
      this._primary.offAny(this._$handlePrimaryAny);
    },
    _clear: function () {
      BaseClass.prototype._clear.call(this);
      this._primary = null;
      this._secondary = null;
      this._lastSecondary = null;
      this._$handleSecondaryAny = null;
      this._$handlePrimaryAny = null;
      this._free();
    }
  };
}

function createStream$1(name, mixin) {
  var S = createConstructor$1(Stream, name);
  inherit(S, Stream, createClassMethods$1(Stream), mixin);
  return S;
}

function createProperty$1(name, mixin) {
  var P = createConstructor$1(Property, name);
  inherit(P, Property, createClassMethods$1(Property), mixin);
  return P;
}

var mixin$26 = {
  _handlePrimaryValue: function (x) {
    if (this._lastSecondary !== NOTHING && this._lastSecondary) {
      this._emitValue(x);
    }
  },
  _handleSecondaryEnd: function () {
    if (this._lastSecondary === NOTHING || !this._lastSecondary) {
      this._emitEnd();
    }
  }
};

var S$34 = createStream$1('filterBy', mixin$26);
var P$29 = createProperty$1('filterBy', mixin$26);

function filterBy(primary, secondary) {
  return new (primary._ofSameType(S$34, P$29))(primary, secondary);
}

var id2 = function (_, x) {
  return x;
};

function sampledBy(passive, active, combinator) {
  var _combinator = combinator ? function (a, b) {
    return combinator(b, a);
  } : id2;
  return combine([active], [passive], _combinator).setName(passive, 'sampledBy');
}

var mixin$27 = {
  _handlePrimaryValue: function (x) {
    if (this._lastSecondary !== NOTHING) {
      this._emitValue(x);
    }
  },
  _handleSecondaryEnd: function () {
    if (this._lastSecondary === NOTHING) {
      this._emitEnd();
    }
  }
};

var S$35 = createStream$1('skipUntilBy', mixin$27);
var P$30 = createProperty$1('skipUntilBy', mixin$27);

function skipUntilBy(primary, secondary) {
  return new (primary._ofSameType(S$35, P$30))(primary, secondary);
}

var mixin$28 = {
  _handleSecondaryValue: function () {
    this._emitEnd();
  }
};

var S$36 = createStream$1('takeUntilBy', mixin$28);
var P$31 = createProperty$1('takeUntilBy', mixin$28);

function takeUntilBy(primary, secondary) {
  return new (primary._ofSameType(S$36, P$31))(primary, secondary);
}

var mixin$29 = {
  _init: function () {
    var _ref = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {},
        _ref$flushOnEnd = _ref.flushOnEnd,
        flushOnEnd = _ref$flushOnEnd === undefined ? true : _ref$flushOnEnd;

    this._buff = [];
    this._flushOnEnd = flushOnEnd;
  },
  _free: function () {
    this._buff = null;
  },
  _flush: function () {
    if (this._buff !== null) {
      this._emitValue(this._buff);
      this._buff = [];
    }
  },
  _handlePrimaryEnd: function () {
    if (this._flushOnEnd) {
      this._flush();
    }
    this._emitEnd();
  },
  _onActivation: function () {
    this._primary.onAny(this._$handlePrimaryAny);
    if (this._alive && this._secondary !== null) {
      this._secondary.onAny(this._$handleSecondaryAny);
    }
  },
  _handlePrimaryValue: function (x) {
    this._buff.push(x);
  },
  _handleSecondaryValue: function () {
    this._flush();
  },
  _handleSecondaryEnd: function () {
    if (!this._flushOnEnd) {
      this._emitEnd();
    }
  }
};

var S$37 = createStream$1('bufferBy', mixin$29);
var P$32 = createProperty$1('bufferBy', mixin$29);

function bufferBy(primary, secondary, options /* optional */) {
  return new (primary._ofSameType(S$37, P$32))(primary, secondary, options);
}

var mixin$30 = {
  _init: function () {
    var _ref = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {},
        _ref$flushOnEnd = _ref.flushOnEnd,
        flushOnEnd = _ref$flushOnEnd === undefined ? true : _ref$flushOnEnd,
        _ref$flushOnChange = _ref.flushOnChange,
        flushOnChange = _ref$flushOnChange === undefined ? false : _ref$flushOnChange;

    this._buff = [];
    this._flushOnEnd = flushOnEnd;
    this._flushOnChange = flushOnChange;
  },
  _free: function () {
    this._buff = null;
  },
  _flush: function () {
    if (this._buff !== null) {
      this._emitValue(this._buff);
      this._buff = [];
    }
  },
  _handlePrimaryEnd: function () {
    if (this._flushOnEnd) {
      this._flush();
    }
    this._emitEnd();
  },
  _handlePrimaryValue: function (x) {
    this._buff.push(x);
    if (this._lastSecondary !== NOTHING && !this._lastSecondary) {
      this._flush();
    }
  },
  _handleSecondaryEnd: function () {
    if (!this._flushOnEnd && (this._lastSecondary === NOTHING || this._lastSecondary)) {
      this._emitEnd();
    }
  },
  _handleSecondaryValue: function (x) {
    if (this._flushOnChange && !x) {
      this._flush();
    }

    // from default _handleSecondaryValue
    this._lastSecondary = x;
  }
};

var S$38 = createStream$1('bufferWhileBy', mixin$30);
var P$33 = createProperty$1('bufferWhileBy', mixin$30);

function bufferWhileBy(primary, secondary, options /* optional */) {
  return new (primary._ofSameType(S$38, P$33))(primary, secondary, options);
}

var f = function () {
  return false;
};
var t = function () {
  return true;
};

function awaiting(a, b) {
  var result = merge([map$1(a, t), map$1(b, f)]);
  result = skipDuplicates(result);
  result = toProperty(result, f);
  return result.setName(a, 'awaiting');
}

var mixin$31 = {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
  },
  _free: function () {
    this._fn = null;
  },
  _handleValue: function (x) {
    var fn = this._fn;
    var result = fn(x);
    if (result.convert) {
      this._emitError(result.error);
    } else {
      this._emitValue(x);
    }
  }
};

var S$39 = createStream('valuesToErrors', mixin$31);
var P$34 = createProperty('valuesToErrors', mixin$31);

var defFn = function (x) {
  return { convert: true, error: x };
};

function valuesToErrors(obs) {
  var fn = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : defFn;

  return new (obs._ofSameType(S$39, P$34))(obs, { fn: fn });
}

var mixin$32 = {
  _init: function (_ref) {
    var fn = _ref.fn;

    this._fn = fn;
  },
  _free: function () {
    this._fn = null;
  },
  _handleError: function (x) {
    var fn = this._fn;
    var result = fn(x);
    if (result.convert) {
      this._emitValue(result.value);
    } else {
      this._emitError(x);
    }
  }
};

var S$40 = createStream('errorsToValues', mixin$32);
var P$35 = createProperty('errorsToValues', mixin$32);

var defFn$1 = function (x) {
  return { convert: true, value: x };
};

function errorsToValues(obs) {
  var fn = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : defFn$1;

  return new (obs._ofSameType(S$40, P$35))(obs, { fn: fn });
}

var mixin$33 = {
  _handleError: function (x) {
    this._emitError(x);
    this._emitEnd();
  }
};

var S$41 = createStream('endOnError', mixin$33);
var P$36 = createProperty('endOnError', mixin$33);

function endOnError(obs) {
  return new (obs._ofSameType(S$41, P$36))(obs);
}

// Create a stream
// -----------------------------------------------------------------------------

// () -> Stream
// (number, any) -> Stream
// (number, any) -> Stream
// (number, Array<any>) -> Stream
// (number, Function) -> Stream
// (number, Function) -> Stream
// (Function) -> Stream
// (Function) -> Stream
// Target = {addEventListener, removeEventListener}|{addListener, removeListener}|{on, off}
// (Target, string, Function|undefined) -> Stream
// (Function) -> Stream
// Create a property
// -----------------------------------------------------------------------------

// (any) -> Property
// (any) -> Property
// Convert observables
// -----------------------------------------------------------------------------

// (Stream|Property, Function|undefined) -> Property
Observable.prototype.toProperty = function (fn) {
  return toProperty(this, fn);
};

// (Stream|Property) -> Stream
Observable.prototype.changes = function () {
  return changes(this);
};

// Interoperation with other implimentations
// -----------------------------------------------------------------------------

// (Promise) -> Property
// (Stream|Property, Function|undefined) -> Promise
Observable.prototype.toPromise = function (Promise) {
  return toPromise(this, Promise);
};

// (ESObservable) -> Stream
// (Stream|Property) -> ES7 Observable
Observable.prototype.toESObservable = toESObservable;
Observable.prototype[$$observable] = toESObservable;

// Modify an observable
// -----------------------------------------------------------------------------

// (Stream, Function|undefined) -> Stream
// (Property, Function|undefined) -> Property
Observable.prototype.map = function (fn) {
  return map$1(this, fn);
};

// (Stream, Function|undefined) -> Stream
// (Property, Function|undefined) -> Property
Observable.prototype.filter = function (fn) {
  return filter(this, fn);
};

// (Stream, number) -> Stream
// (Property, number) -> Property
Observable.prototype.take = function (n) {
  return take(this, n);
};

// (Stream, number) -> Stream
// (Property, number) -> Property
Observable.prototype.takeErrors = function (n) {
  return takeErrors(this, n);
};

// (Stream, Function|undefined) -> Stream
// (Property, Function|undefined) -> Property
Observable.prototype.takeWhile = function (fn) {
  return takeWhile(this, fn);
};

// (Stream) -> Stream
// (Property) -> Property
Observable.prototype.last = function () {
  return last(this);
};

// (Stream, number) -> Stream
// (Property, number) -> Property
Observable.prototype.skip = function (n) {
  return skip(this, n);
};

// (Stream, Function|undefined) -> Stream
// (Property, Function|undefined) -> Property
Observable.prototype.skipWhile = function (fn) {
  return skipWhile(this, fn);
};

// (Stream, Function|undefined) -> Stream
// (Property, Function|undefined) -> Property
Observable.prototype.skipDuplicates = function (fn) {
  return skipDuplicates(this, fn);
};

// (Stream, Function|falsey, any|undefined) -> Stream
// (Property, Function|falsey, any|undefined) -> Property
Observable.prototype.diff = function (fn, seed) {
  return diff(this, fn, seed);
};

// (Stream|Property, Function, any|undefined) -> Property
Observable.prototype.scan = function (fn, seed) {
  return scan(this, fn, seed);
};

// (Stream, Function|undefined) -> Stream
// (Property, Function|undefined) -> Property
Observable.prototype.flatten = function (fn) {
  return flatten(this, fn);
};

// (Stream, number) -> Stream
// (Property, number) -> Property
Observable.prototype.delay = function (wait) {
  return delay(this, wait);
};

// Options = {leading: boolean|undefined, trailing: boolean|undefined}
// (Stream, number, Options|undefined) -> Stream
// (Property, number, Options|undefined) -> Property
Observable.prototype.throttle = function (wait, options) {
  return throttle(this, wait, options);
};

// Options = {immediate: boolean|undefined}
// (Stream, number, Options|undefined) -> Stream
// (Property, number, Options|undefined) -> Property
Observable.prototype.debounce = function (wait, options) {
  return debounce(this, wait, options);
};

// (Stream, Function|undefined) -> Stream
// (Property, Function|undefined) -> Property
Observable.prototype.mapErrors = function (fn) {
  return mapErrors(this, fn);
};

// (Stream, Function|undefined) -> Stream
// (Property, Function|undefined) -> Property
Observable.prototype.filterErrors = function (fn) {
  return filterErrors(this, fn);
};

// (Stream) -> Stream
// (Property) -> Property
Observable.prototype.ignoreValues = function () {
  return ignoreValues(this);
};

// (Stream) -> Stream
// (Property) -> Property
Observable.prototype.ignoreErrors = function () {
  return ignoreErrors(this);
};

// (Stream) -> Stream
// (Property) -> Property
Observable.prototype.ignoreEnd = function () {
  return ignoreEnd(this);
};

// (Stream, Function) -> Stream
// (Property, Function) -> Property
Observable.prototype.beforeEnd = function (fn) {
  return beforeEnd(this, fn);
};

// (Stream, number, number|undefined) -> Stream
// (Property, number, number|undefined) -> Property
Observable.prototype.slidingWindow = function (max, min) {
  return slidingWindow(this, max, min);
};

// Options = {flushOnEnd: boolean|undefined}
// (Stream, Function|falsey, Options|undefined) -> Stream
// (Property, Function|falsey, Options|undefined) -> Property
Observable.prototype.bufferWhile = function (fn, options) {
  return bufferWhile(this, fn, options);
};

// (Stream, number) -> Stream
// (Property, number) -> Property
Observable.prototype.bufferWithCount = function (count, options) {
  return bufferWhile$1(this, count, options);
};

// Options = {flushOnEnd: boolean|undefined}
// (Stream, number, number, Options|undefined) -> Stream
// (Property, number, number, Options|undefined) -> Property
Observable.prototype.bufferWithTimeOrCount = function (wait, count, options) {
  return bufferWithTimeOrCount(this, wait, count, options);
};

// (Stream, Function) -> Stream
// (Property, Function) -> Property
Observable.prototype.transduce = function (transducer) {
  return transduce(this, transducer);
};

// (Stream, Function) -> Stream
// (Property, Function) -> Property
Observable.prototype.withHandler = function (fn) {
  return withHandler(this, fn);
};

// (Stream, Stream -> a) -> a
// (Property, Property -> a) -> a
Observable.prototype.thru = function (fn) {
  return fn(this);
};

// Combine observables
// -----------------------------------------------------------------------------

// (Array<Stream|Property>, Function|undefiend) -> Stream
// (Array<Stream|Property>, Array<Stream|Property>, Function|undefiend) -> Stream
Observable.prototype.combine = function (other, combinator) {
  return combine([this, other], combinator);
};

// (Array<Stream|Property>, Function|undefiend) -> Stream
Observable.prototype.zip = function (other, combinator) {
  return zip([this, other], combinator);
};

// (Array<Stream|Property>) -> Stream
Observable.prototype.merge = function (other) {
  return merge([this, other]);
};

// (Array<Stream|Property>) -> Stream
Observable.prototype.concat = function (other) {
  return concat$1([this, other]);
};

// () -> Pool
var pool = function () {
  return new Pool();
};

// (Function) -> Stream
// Options = {concurLim: number|undefined, queueLim: number|undefined, drop: 'old'|'new'|undefiend}
// (Stream|Property, Function|falsey, Options|undefined) -> Stream
Observable.prototype.flatMap = function (fn) {
  return new FlatMap(this, fn).setName(this, 'flatMap');
};
Observable.prototype.flatMapLatest = function (fn) {
  return new FlatMap(this, fn, { concurLim: 1, drop: 'old' }).setName(this, 'flatMapLatest');
};
Observable.prototype.flatMapFirst = function (fn) {
  return new FlatMap(this, fn, { concurLim: 1 }).setName(this, 'flatMapFirst');
};
Observable.prototype.flatMapConcat = function (fn) {
  return new FlatMap(this, fn, { queueLim: -1, concurLim: 1 }).setName(this, 'flatMapConcat');
};
Observable.prototype.flatMapConcurLimit = function (fn, limit) {
  return new FlatMap(this, fn, { queueLim: -1, concurLim: limit }).setName(this, 'flatMapConcurLimit');
};

// (Stream|Property, Function|falsey) -> Stream
Observable.prototype.flatMapErrors = function (fn) {
  return new FlatMapErrors(this, fn).setName(this, 'flatMapErrors');
};

// Combine two observables
// -----------------------------------------------------------------------------

// (Stream, Stream|Property) -> Stream
// (Property, Stream|Property) -> Property
Observable.prototype.filterBy = function (other) {
  return filterBy(this, other);
};

// (Stream, Stream|Property, Function|undefiend) -> Stream
// (Property, Stream|Property, Function|undefiend) -> Property
Observable.prototype.sampledBy = function (other, combinator) {
  return sampledBy(this, other, combinator);
};

// (Stream, Stream|Property) -> Stream
// (Property, Stream|Property) -> Property
Observable.prototype.skipUntilBy = function (other) {
  return skipUntilBy(this, other);
};

// (Stream, Stream|Property) -> Stream
// (Property, Stream|Property) -> Property
Observable.prototype.takeUntilBy = function (other) {
  return takeUntilBy(this, other);
};

// Options = {flushOnEnd: boolean|undefined}
// (Stream, Stream|Property, Options|undefined) -> Stream
// (Property, Stream|Property, Options|undefined) -> Property
Observable.prototype.bufferBy = function (other, options) {
  return bufferBy(this, other, options);
};

// Options = {flushOnEnd: boolean|undefined}
// (Stream, Stream|Property, Options|undefined) -> Stream
// (Property, Stream|Property, Options|undefined) -> Property
Observable.prototype.bufferWhileBy = function (other, options) {
  return bufferWhileBy(this, other, options);
};

// Deprecated
// -----------------------------------------------------------------------------

var DEPRECATION_WARNINGS = true;
function dissableDeprecationWarnings() {
  DEPRECATION_WARNINGS = false;
}

function warn(msg) {
  if (DEPRECATION_WARNINGS && console && typeof console.warn === 'function') {
    var msg2 = '\nHere is an Error object for you containing the call stack:';
    console.warn(msg, msg2, new Error());
  }
}

// (Stream|Property, Stream|Property) -> Property
Observable.prototype.awaiting = function (other) {
  warn('You are using deprecated .awaiting() method, see https://github.com/kefirjs/kefir/issues/145');
  return awaiting(this, other);
};

// (Stream, Function|undefined) -> Stream
// (Property, Function|undefined) -> Property
Observable.prototype.valuesToErrors = function (fn) {
  warn('You are using deprecated .valuesToErrors() method, see https://github.com/kefirjs/kefir/issues/149');
  return valuesToErrors(this, fn);
};

// (Stream, Function|undefined) -> Stream
// (Property, Function|undefined) -> Property
Observable.prototype.errorsToValues = function (fn) {
  warn('You are using deprecated .errorsToValues() method, see https://github.com/kefirjs/kefir/issues/149');
  return errorsToValues(this, fn);
};

// (Stream) -> Stream
// (Property) -> Property
Observable.prototype.endOnError = function () {
  warn('You are using deprecated .endOnError() method, see https://github.com/kefirjs/kefir/issues/150');
  return endOnError(this);
};

// Exports
// --------------------------------------------------------------------------

var Kefir = {
  Observable: Observable,
  Stream: Stream,
  Property: Property,
  never: never,
  later: later,
  interval: interval,
  sequentially: sequentially,
  fromPoll: fromPoll,
  withInterval: withInterval,
  fromCallback: fromCallback,
  fromNodeCallback: fromNodeCallback,
  fromEvents: fromEvents,
  stream: stream,
  constant: constant,
  constantError: constantError,
  fromPromise: fromPromise,
  fromESObservable: fromESObservable,
  combine: combine,
  zip: zip,
  merge: merge,
  concat: concat$1,
  Pool: Pool,
  pool: pool,
  repeat: repeat,
  staticLand: staticLand
};

Kefir.Kefir = Kefir;

export { dissableDeprecationWarnings, Kefir, Observable, Stream, Property, never, later, interval, sequentially, fromPoll, withInterval, fromCallback, fromNodeCallback, fromEvents, stream, constant, constantError, fromPromise, fromESObservable, combine, zip, merge, concat$1 as concat, Pool, pool, repeat, staticLand };export default Kefir;