2715-timeout-cancellation.js

/**
 * 2715. Timeout Cancellation
 * https://leetcode.com/problems/timeout-cancellation/
 * Difficulty: Easy
 *
 * Given a function fn, an array of arguments args, and a timeout t in milliseconds,
 * return a cancel function cancelFn.
 *
 * After a delay of cancelTimeMs, the returned cancel function cancelFn will be invoked.
 * > setTimeout(cancelFn, cancelTimeMs)
 *
 * Initially, the execution of the function fn should be delayed by t milliseconds.
 *
 * If, before the delay of t milliseconds, the function cancelFn is invoked, it should
 * cancel the delayed execution of fn. Otherwise, if cancelFn is not invoked within the
 * specified delay t, fn should be executed with the provided args as arguments.
 */

/**
 * @param {Function} fn
 * @param {Array} args
 * @param {number} t
 * @return {Function}
 */
var cancellable = function(fn, args, t) {
  const timeoutId = setTimeout(() => fn(...args), t);
  return () => clearTimeout(timeoutId);
};