JavaScript · Senior · Question 64 of 75

Why do schedulers (e.g. React's) use `MessageChannel` instead of `setTimeout(fn, 0)`?

✓Correct answer: Posting a message schedules a macrotask without the ~4ms clamping of nested timers
2MessageChannel runs code in a worker
3setTimeout doesn't run in background tabs

Explanation

Nested setTimeout calls are clamped to at least 4ms by the HTML spec. A message event yields to the browser for rendering and input, then continues quickly.

Why do schedulers (e.g. React's) use `MessageChannel` instead of `setTimeout(fn, 0)`?

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Why do schedulers (e.g. React's) use MessageChannel instead of setTimeout(fn, 0)?

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Why do schedulers (e.g. React's) use `MessageChannel` instead of `setTimeout(fn, 0)`?