Javascript イベントを遅らせて発火させる

  class DelayWork {
    constructor (callBackFunc, wait = 500) {
      this.callBackFunc = callBackFunc; // func.bind (this)
      this.wait = wait;
      this.timerID = null;
    }

    start (...arg) {
      if (! this.timerID) {
        let cbfunc = () => {
          this.timerID = null;
          this.callBackFunc (...arg);
         };
        this.timerID = setTimeout (cbfunc, this.wait);
       }
      return this;
    }


    stop () {
      if (this.timerID)
        clearTimeout (this.timerID);
      this.timerID = null;
      return this;
    }
  }

  //_____________________________________________________


  class DelayHandler {

    constructor (handler, wait = 300) {
      let cbFunc;
      switch (Object.prototype.toString.call (handler)) {
      case '[object Object]' :
        if ('handleEvent' in handler)
          if ('function' === typeof handler.handleEvent)
            cbFunc = handler.handleEvent.bind (handler);
        break;

      case '[object Function]' :
        cbFunc = handler; break;

      default:
        throw new Error ('Not handleEvent'); break;
      }

      this.handler = new DelayWork (cbFunc, this.wait);
      this.wait = wait;
    }


    handleEvent (event) {
      this.handler.stop ().start (event);
    }
  }

//_____________________________________________________

function handler (event) {
  ;
}

document.querySelector ('input[type="search"]')
  .addEventListener ('input', new DelayHandler (handler), false);