streamtester.js

import { EventEmitter } from 'events';

class StreamTester extends EventEmitter {
  constructor() {
    super();

    this._done = false;

    this._emitter1 = null;
    this._emitter2 = null;
    this._emitter3 = null;
    this._stopEmitters = null;

    process.nextTick(() => {
      this._startEmitters();
    });
  }

  _startEmitters() {
    if (this._done) {
      return;
    }
    this._emitter1 = setInterval(() => this.emit('data', 'emitter 1'), 280);
    this._emitter2 = setInterval(() => this.emit('data', 'emitter 2'), 580);
    this._emitter3 = setInterval(() => this.emit('data', 'emitter 3'), 740);
    this._stopEmitters = setTimeout(() => {
      this._pauseEmitters();
      this._done = true;
      this.emit('end');
    }, 1500);
  }

  _pauseEmitters() {
    if (this._done) {
      return;
    }
    clearInterval(this._emitter1);
    clearInterval(this._emitter2);
    clearInterval(this._emitter3);
  }

  pause() {
    this._pauseEmitters();
  }

  resume() {
    this._startEmitters();
  }
}