@so-dang-cool/sleep 💤

Pause execution, for TS/JS.

import { sleep } from "@so-dang-cool/sleep"

console.log("Let's begin.");
await sleep.millis(500);

console.log("Wait a second!");
await sleep.seconds(1);

console.log("Now wait just half a minute!");
await sleep.minutes(1/2);

console.log("Wait until next week! (good luck)");
const oneWeek = 1000 * 60 * 60 * 24 * 7;
await sleep.until(Date.now() + oneWeek);

// Also:
//
// sleep.hours(...);
// sleep.days(...);
//
// sleep(...) by itself also takes milliseconds.

// Promise-based chaining also works:
sleep.seconds(1).then(() => fetch(/* etc /*));

DIY

If you prefer to avoid dependencies, these are the mechanics of the sleep(...) and sleep.<duration>(...) functions:

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

// Wait 1 second
await sleep(1000);

async and await are syntactic sugar over the Promise built-in object in JavaScript. A Promise works by considering itself incomplete when created, and passes functions of resolve and reject that can be used to report completion. We make the built-in function setTimeout(...) report a successful completion with resolve and await the results. Voila, we can now pause execution with millisecond-level granularity.

This is a publicly well-known pattern in JavaScript, and numerous examples existed before this library. You do not have to reference this project in order to implement your own version of sleep(...).

Etc

Oct 2024, by J.R. Hill

BSD 3-Clause License