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const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

JavaScript · general · type the snippet below to practice

wpm0

acc100%

time–

def fib(n): a, b = 0, 1 for _ in range(n): a, b = b, a + b return a

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about this snippet

This is the sleep snippet in JavaScript — 12 lines of real JavaScript code that exercises common patterns you'll see in production. DeveloperType scores you on net WPM and accuracy and only counts runs above 95% accuracy on the leaderboard, so practice rewards precision, not speed alone.

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const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

async function poll(fn, { interval = 500, timeout = 5000 } = {}) {
  const start = Date.now();
  while (Date.now() - start < timeout) {
    const value = await fn();
    if (value) return value;
    await sleep(interval);
  }
  throw new Error("poll timed out");
}

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