Pause Until

Pauses the execution of a function until you choose to continue or until a timeout expires.

pause() returns a promise that resolves when you call resume(), or when a timeout expires.

Basic example

The search() function relies on the data cached in memory. We want to pause this function and let it continue only when the data is loaded.

const { pause, resume } = require('pause-until');

let data = null;

async function search(searchWhat) {
	if (!data) {
		// We'll wait here until the data is loaded:
		await pause('data loaded');
	}

	findInData(data, what);
}

async function loadDataIntoMemory() {
  data = getDataFromSomewhere();

  // Calling this will resume the search() function:
  resume('data loaded');
}

loadDataIntoMemory();

Don't wait forever - add a timeout

In the same example as above, we will pause the search() function for 15 seconds at most, since we don't want to get stuck forever:

const { pause, resume } = require('pause-until');

let data = null;

async function search(searchWhat) {
	if (!data) {
		// We'll wait here until the data is loaded,
		// but for 15 seconds maximum:
		await pause('data loaded', 15000);
	}

	findInData(data, what);
}

async function loadDataIntoMemory() {
  data = getDataFromSomewhere();

  // Calling this will resume the search() function:
  resume('data loaded');
}

loadDataIntoMemory();

Throw an exception instead of continue if we hit the timeout

const { pause, resume } = require('pause-until');

let data = {};

async function search(searchWhat) {
	if (!data) {
		// We'll wait here until the data is loaded,
		// but for 15 seconds maximum:
		await pause('data loaded', 15000, true);
	}

	findInData(data, what);
}

async function loadDataIntoMemory() {
  data = getDataFromSomewhere();

  // Calling this will resume the search() function:
  resume('data loaded');
}

loadDataIntoMemory();

Methods

All methods in this class are static. There are two methods: pause() and resume(). You can add them into your code in one of the two ways:

const { pause, resume } = require('pause-until');
// You can call pause(), resume() now.


// Or:
const Tasks = require('pause-until');
// You can call Tasks.pause(), Tasks.resume() now.

static async pause(identifier, timeout, reject)

Returns a promise that resolves when resume() is called or when a timeout expires.

• identifier - An arbitrary identifier. Must be passed to resume() when unpausing.
• timeout - Optional: resolve the promise automatically after this many milliseconds if it's not resolved yet.
• reject - Optional: if the promise times out without being resolved (by using the timeout parameter), reject the promise instead of resolving it.

static async resume(identifier)

Resolves the promise created by pause().

• identifier - An arbitrary identifier. Must be the same as the one used with pause().