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remote-promises

Create native ES6 promises and resolve them externally.

Get Started

Ensure its installed as a dependency from your console:

npm i remote-promises

Then import the RemotePromise class before attempting the following examples

import { RemotePromise } from 'remote-promises'

Remotely Controlling the Promise

I guess this is why you're here – use .resolve() or .reject() to satisfy the promise.

When you do this, the status property changes from "pending" to either "resolved" or "rejected".

// Instantiate a new remote promise
const rp = new RemotePromise()

rp.resolve('some resolved value')
//- rp.reject(new Error("500: The whole system's blown!"))

rp.status // 'resolved'

Awaiting a Remote Promise

RemotePromise can be used with the await keyword just like the native promises.

const rp = new RemotePromise()
rp.resolve('any value')

// Use await in an asynchronous context
(async () => {
  console.log(await rp) // 'any value'
})()

But when await is used with a rejected promise, the rejection is thrown like an error and can be caught.

const rp = new RemotePromise()

// Gotta catch 'em all!
(async () => {
  try {
    await rp
  } catch (reason) {
    console.log(reason) // 'pocket monsters'
  }
})()

rp.reject('pocket monsters')

Using Then and Catch

If you're not a fan of the async/await style, then you can use then/catch as you normally would with promises. These can be chained too.

const rp = new RemotePromise()

// then/catch can be called the promise is satisfied
rp.then(value => console.log('success', value))
rp.catch(reason => console.log('flop', reason)) // 'flop', 'fish'

// Satisfy the promise
rp.reject('fish')

// Cheeky little example involving chains
rp
  .catch(() => 'flip')
  .then(value => console.log(value)) // 'flip'

Involving Types for TypeScript

As with the native promises, you're able to define an interface for a fulfilled promise value.

// Define your structure
interface SomeStructure {
  status: 200
  result: string
}

// Create a new typed remote promise
const rp = new RemotePromise<SomeStructure>()

// Must resolve with an object according to the type
rp.resolve({
  status: 200,
  result: 'samosas'
})

// Start writing a callback...
rp.then(val => {
  // val is of type SomeStructure
})