debounce.js

function debounce(callback, timer) {
  let timeoutId;

  return (...args) => {
    // save the current context (this)
    const context = this;

    // clear the existing timeout
    clearTimeout(timeoutId);

    // create a new timeout
    timeoutId = setTimeout(() => {
      callback.apply(context, args);
    }, timer);
  };
}