Timeout cancellation

89.7% acceptance

Mar 2, 2026

317

370

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.

Solution

TypeScript

Time O(1)

Space O(1)

LeetCode

solution.ts

type JSONValue =
  | null
  | boolean
  | number
  | string
  | JSONValue[]
  | { [key: string]: JSONValue };
type Fn = (...args: JSONValue[]) => void;

function cancellable(fn: Fn, args: JSONValue[], t: number): Function {
  const timer = setTimeout(() => fn(...args), t);
  return function () {
  clearTimeout(timer);
  };
}

/**
 *  const result = [];
 *
 *  const fn = (x) => x * 5;
 *  const args = [2], t = 20, cancelTimeMs = 50;
 *
 *  const cancel = cancellable(log, args, t);
 *  setTimeout(cancel, cancelTimeMs);
 */