kefir/src/primary/stream.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 Stream from '../stream'
import emitter from '../emitter'

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

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

  _onActivation() {
    const fn = this._fn
    const 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() {
    if (this._unsubscribe !== null) {
      this._unsubscribe()
      this._unsubscribe = null
    }
  },

  _onDeactivation() {
    this._callUnsubscribe()
  },

  _clear() {
    Stream.prototype._clear.call(this)
    this._fn = null
  },
})

export default function stream(fn) {
  return new S(fn)
}