timeout-cancellation.js

//2715. Timeout Cancellation

/*
Given a function fn, an array of arguments args, and a timeout t in milliseconds, return a cancel function cancelFn.

After a delay of t, fn should be called with args passed as parameters unless cancelFn was invoked before the delay of t milliseconds elapses, specifically at cancelT ms. In that case, fn should never be called.
*/

var cancellable = function(fn, args, t) {
  const timeoutId = setTimeout(function() {
    fn.apply(null, args);
  }, t);

  const cancelFn = function() {
    clearTimeout(timeoutId);
  };

  return cancelFn;
};