debounce.js

(function () {
  
  window.debounce = function(callback, ms) {
    var isCooldown = false;

    return function() {
      if (isCooldown) return;

      callback.apply(this, arguments);

      isCooldown = true;

      setTimeout(function() {
        isCooldown = false;
      }, ms);
    };

  }
})();
 
 // использование
var button = ...;

var onClick = function(evt) {
  console.log('test', evt);
}

var deboucedOnClick = window.debounce(onClick, 500);
button.addEventListener('click', deboucedOnClick);