Cancellable Interval

easycodingJavaScriptTimingFunctions~10 min

Asked at Google, Meta, Amazon

Overview

Implement createInterval(callback, delay) that calls callback every delay ms and returns a cancel function.

Examples

let count = 0;
const cancel = createInterval(() => count++, 100);
setTimeout(cancel, 250);
// count is 2

Solution

Reveal solution

function createInterval(callback, delay) {
  const id = setInterval(callback, delay);
  return function cancel() { clearInterval(id); };
}

cancellable-interval.js

Cancellable Interval

easycodingJavaScriptTiming

Overview

Implement createInterval(callback, delay) that calls callback every delay ms and returns a cancel function.

Examples

let count = 0;
const cancel = createInterval(() => count++, 100);
setTimeout(cancel, 250);
// count is 2

Solution

Reveal solution

function createInterval(callback, delay) {
  const id = setInterval(callback, delay);
  return function cancel() { clearInterval(id); };
}

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