kefir/src/property.js

Reactive Programming library for JavaScript inspired by Bacon.js and RxJS with focus on high performance and low memory usage

import {inherit} from './utils/objects'
import {VALUE, ERROR, END} from './constants'
import {callSubscriber} from './dispatcher'
import Observable from './observable'

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

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

  _emitValue(value) {
    if (this._alive) {
      this._currentEvent = {type: VALUE, value}
      if (!this._activating) {
        this._dispatcher.dispatch({type: VALUE, value})
      }
    }
  },

  _emitError(value) {
    if (this._alive) {
      this._currentEvent = {type: ERROR, value}
      if (!this._activating) {
        this._dispatcher.dispatch({type: ERROR, value})
      }
    }
  },

  _emitEnd() {
    if (this._alive) {
      this._alive = false
      if (!this._activating) {
        this._dispatcher.dispatch({type: END})
      }
      this._clear()
    }
  },

  _on(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() {
    return 'property'
  },
})

export default Property