sleep-promise

What is sleep-promise?

The 'sleep-promise' npm package provides a simple way to pause the execution of asynchronous code for a specified duration. It returns a promise that resolves after the given time, making it useful for delaying operations in a non-blocking manner.

What are sleep-promise's main functionalities?

Basic Sleep

This feature allows you to pause the execution of your code for a specified duration. In this example, the code pauses for 2 seconds between logging 'Start' and 'End'.

const sleep = require('sleep-promise');

async function example() {
  console.log('Start');
  await sleep(2000); // Sleep for 2 seconds
  console.log('End');
}

example();

Sleep with Error Handling

This feature demonstrates how to handle errors that might occur during the sleep operation. Although 'sleep-promise' itself does not throw errors, this pattern is useful for more complex scenarios where other asynchronous operations might fail.

const sleep = require('sleep-promise');

async function example() {
  try {
    console.log('Start');
    await sleep(2000); // Sleep for 2 seconds
    console.log('End');
  } catch (error) {
    console.error('An error occurred:', error);
  }
}

example();

Other packages similar to sleep-promise

delay

The 'delay' package provides similar functionality to 'sleep-promise' by allowing you to delay the execution of asynchronous code. It also offers additional features like creating cancellable delays and delay loops. Compared to 'sleep-promise', 'delay' is more feature-rich and versatile.

await-sleep

The 'await-sleep' package is another alternative that provides a simple way to pause execution in async functions. It is very similar to 'sleep-promise' in terms of functionality but has a smaller footprint and fewer additional features.

README

sleep-promise

sleep-promise resolves a promise after a specified delay.

Installation

node.js

npm install sleep-promise

Usage async / await

import sleep from 'sleep-promise';

(async () => {
    await sleep(2000);
    console.log('2 seconds later …');
})();

Usage ES5

var sleep = require('sleep-promise');

sleep(2000).then(function() {
    console.log('2 seconds later …');
});

Usage in a promise chain

import sleep from 'sleep-promise';

let trace = value => {
    console.log(value);
    return value;
};

sleep(2000)
    .then(() => 'hello')
    .then(trace)
    .then(sleep(1000))
    .then(value => value + ' world')
    .then(trace)
    .then(sleep(500))
    .then(value => value + '!')
    .then(trace);

// [2 seconds sleep]
// hello
// [1 second sleep]
// hello world
// [500 ms sleep]
// hello world!

Usage in a test file that mocks setTimeout

import sinon from 'sinon';
import sleep from 'sleep-promise';

const clock = sinon.useFakeTimers();

(async () => {
    // 2 seconds faked by sinon
    const sleepPromise = sleep(2000);
    clock.tick(2000);
    await sleepPromise;
    console.log('instant');

    // Caches global setTimeout before sinon replaced it
    const sleepPromise2 = sleep(2000, { useCachedSetTimeout: true });
    clock.tick(2000);
    await sleepPromise2;
    console.log('2 seconds later');
})();

License

MIT