kefir/src/one-source/buffer-with-count.js

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

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

const mixin = {
  _init({count, flushOnEnd}) {
    this._count = count
    this._flushOnEnd = flushOnEnd
    this._buff = []
  },

  _free() {
    this._buff = null
  },

  _flush() {
    if (this._buff !== null && this._buff.length !== 0) {
      this._emitValue(this._buff)
      this._buff = []
    }
  },

  _handleValue(x) {
    this._buff.push(x)
    if (this._buff.length >= this._count) {
      this._flush()
    }
  },

  _handleEnd() {
    if (this._flushOnEnd) {
      this._flush()
    }
    this._emitEnd()
  },
}

const S = createStream('bufferWithCount', mixin)
const P = createProperty('bufferWithCount', mixin)

export default function bufferWhile(obs, count, {flushOnEnd = true} = {}) {
  return new (obs._ofSameType(S, P))(obs, {count: count, flushOnEnd})
}