deferred.md

Deferred

When creating a Promise in Javascript, it can be helpful to resolve or reject that promise from outside of the created promise's scope. However, Javascript's built-in Promise API does not provide a native solution.

Deferred is meant to allow developers to freely create promises and then resolve or reject them from anywhere in their code, as long as they have a reference to the created Deferred object.

Example Usage

import { Deferred } from '@unifire-js/async';

async function test() {
    // Create a deferred promise
    const deferred = new Deferred();

    // After 3 seconds, resolve the deferred promise with the value, "Test"
    setTimeout(() => {
        deferred.resolve('Test');
    }, 3000);

    // Obtain the result of deferred once it has resolved
    const deferredResult = await deferred.promise;

    console.log(deferredResult); // 'Test'
}

Constructor Arguments

Argument	Type	Description
None	None	None

Properties

Property	Type	Description
promise	Promise	The native Javascript promise stored by Deferred.
settled	boolean	Flag indicating whether the internal promise has resolved.

Methods

Method	Return	Description
resolve(*)	null	The native Javascript promise.resolve function used to resolve the native promise stored by Deferred.
reject(*)	null	The native Javascript promise.reject function used to reject the native promise stored by Deferred.

Static Methods

Method	Return	Description
resolve(*)	Deferred	Creates a new Deferred instance, instantly resolves it, and returns that new instance. The Deferred equivalent of Promise.resolve().
reject(*)	Deferred	Creates a new Deferred instance, instantly rejects it, and returns that new instance. The Deferred equivalent of Promise.reject().