sleep()

sleep(ms): Promise<void>

Pauses execution for a specified duration.

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Parameters

ms: number

Duration to sleep in milliseconds (must be non-negative).

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Returns: Promise<void>

Promise that resolves after the specified duration.

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Throws

RangeError If ms is negative.

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Since

2.0.0

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Also known as

delay (es-toolkit) · sleep (Radashi, Effect, Modern Dash, Antfu) · ❌ (Lodash, Remeda, Ramda)

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Example

await sleep(1000);
console.log('1 second later');

// Sequential delays
for (const item of items) {
  await process(item);
  await sleep(100);
}

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How it works?

Pauses execution for a specified duration. Returns a Promise that resolves after the delay.

Usage

Sequential Delays

Rate limiting between operations.

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Use Cases

Delay async execution 📌

Pause async execution for a specific duration. Essential for throttling, polling intervals, or simulating latency in tests.

#delay#async#pause#sleep#throttle#polling

await sleep(1000); // Wait 1 second
await fetchData();

Respect API rate limits

Introduce delays between batch operations to avoid hitting rate limits.

#respect#rate-limits#throttle#batch#delays#API

for (const item of batch) {
  await sendRequest(item);
  await sleep(100); // 100ms between requests
}

Simulate network latency

Add artificial delays in development/testing environments.

#simulate#latency#network#testing#development#delays

if (isDev) {
  await sleep(500); // Simulate slow network
}
return mockData;