async-short-circuit's Introduction

Async Short Circuit

Performs logical AND and OR operations with short circuit on promises.

Given an array of promises, as soon as a promise whose value can cause a short circuit is resolved, it's value is used and returned and the rest of the promises are ignored.

Install

npm i async-short-circuit

Usage

const { asyncAnd, asyncOr } = require('async-short-circuit');

// or using import
import { asyncAnd, asyncOr } from 'async-short-circuit';

// Some code ...

// AND
asyncAnd(myPromises).then(value => { /* perform some logic with AND result */ });

// OR
asyncOr(myPromises).then(value => { /* perform some logic with OR result */ });

API

asyncAnd(promises): Promise<any> - Returned value depends on the resolve value of the given promises
- promises: an array of Promises.
asyncOr(promises): Promise<any> - Returned value depends on the resolve value of the given promises
- promises: an array of Promises.

Important Notes

Short Circuit Logic

The given promises are awaited upon, and as soon as one of them resolves, it's value is checked, if its value can cause a short circuit, the returned promise -from short-circuit functions- resolves immediately with that value without waiting for the results of the remaining promises. If the value of the resolved promise does not cause a short circuit, it's ignored and the same logic is applies to other promises.

If all none of the encountered value would cause short circuit, then the result of ANDing or ORing all the values is returned, which is the last value (the resolved value of the last promise in the given array) according to JS implementation.

Also note that any short-circuiting does not affect the running of the given promises, all the promises will always run no matter the result, it's just we don't wait for the resolving of the remaining promises if a value is received that causes a short-circuit.