kefir/src/one-source/flatten.js

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

import {createStream} from '../patterns/one-source'

const mixin = {
  _init({fn}) {
    this._fn = fn
  },

  _free() {
    this._fn = null
  },

  _handleValue(x) {
    const fn = this._fn
    const xs = fn(x)
    for (let i = 0; i < xs.length; i++) {
      this._emitValue(xs[i])
    }
  },
}

const S = createStream('flatten', mixin)

const id = x => x

export default function flatten(obs, fn = id) {
  return new S(obs, {fn})
}