Lame JS puzzle #2 debounce requests

fb_debounce.js

/*
If you were building a search tool and wanted search results to pop up as you 
typed but the server call was taxing, write a function that gets called on every 
key down but calls the server when the user stops typing for 400ms. 
*/

// <input type="text" class="js-search">

// Why a IIFE? coz I don't feel like polluting the global scope with crap [happy face]
(() => {
  
let search = document.querySelectorAll('input.js-search');

// Why a IIFE? to allow multiple input.search
// and keep a local parent scope (ie to keep
// lastRequest) for each of them
let onKeyStroke = (() => {
  let lastRequest = null;
  
  // I see closure! a closure bring the entire outer
  // scope wherever it goes, like a hobo
  return function _onKeyStroke(ev) {
  	if (lastRequest != null)
    	clearTimeout(lastRequest);
    
    lastRequest = setTimeout(() => {
    	let params = new URLSearchParams(`q=${this.value}`).toString();

      fetch(`http://localhost/?${params}`)
      .then((response) => {
        console.log(response);
      })
      .catch((error) => {
        console.log(error);
      })
    }, 400);
  }
})();

search.forEach((elem) => elem.addEventListener('input', onKeyStroke));

})()