idle.js

/**
 * Create a function which will call the callback function
 * after the given amount of milliseconds has passed since
 * the last time the callback function was called.
 */
const idle = (callback, delay) => {
  let handle;

  return () => {
    if (handle) {
      clearTimeout(handle);
    }

    handle = setTimeout(callback, delay);
  };
};