Cancellable Timeout

easycodingJavaScriptTimingFunctions~10 min

Asked at Google, Meta, Amazon

Overview

Implement createTimeout(callback, delay) that schedules callback after delay ms and returns a cancel function.

Examples

let called = false;
const cancel = createTimeout(() => { called = true; }, 100);
cancel(); // callback never fires

Solution

Reveal solution

function createTimeout(callback, delay) {
  const id = setTimeout(callback, delay);
  return function cancel() { clearTimeout(id); };
}

cancellable-timeout.js

Cancellable Timeout

easycodingJavaScriptTiming

Overview

Implement createTimeout(callback, delay) that schedules callback after delay ms and returns a cancel function.

Examples

let called = false;
const cancel = createTimeout(() => { called = true; }, 100);
cancel(); // callback never fires

Solution

Reveal solution

function createTimeout(callback, delay) {
  const id = setTimeout(callback, delay);
  return function cancel() { clearTimeout(id); };
}

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