Helper Functions

slow.js

export function throttle(func, ms) {

  let isThrottled = false,
    savedArgs,
    savedThis;

  function wrapper(...args) {

    // memorize all func calls       
    if (isThrottled) {
      savedArgs = args;
      savedThis = this;
      return;
    }

    func.apply(this, args);

    isThrottled = true;

    setTimeout(function() {
      isThrottled = false;
      // the last func call will work after timeout   
      if (savedArgs) {
        wrapper.apply(savedThis, savedArgs);
        savedArgs = savedThis = null;
      }
    }, ms);
  }

  return wrapper;
}

export function debounce(func, ms) {
   let timer = null;

    return function (...args) {
      const onComplete = () => {
        func.apply(this, args);
        timer = null;
      }

      if (timer) {
        clearTimeout(timer);
      }

      timer = setTimeout(onComplete, ms);
    };
}