p-state-defer

A deferred promise with state

Install

npm i p-state-defer

// esm
import Deferred from 'p-state-defer'

// or cjs
const {Deferred} = require('p-state-defer')

Usage

Basic

function loadImage(url){
  // Unlike Promise, No Indent!
  const defer = new Deferred();

  const img = new Image()
  img.src = url
  img.onload = _ => defer.resolve(img)
  img.onerror = _ => defer.reject(new Error('Failed to load image.'))

  return defer.promise;
}

State

const defer = new Deferred();

console.log( defer.isCompleted ) // false
console.log( defer.state ) // "pending"

defer.resolve('hello')

console.log( defer.isCompleted ) // => true
console.log( defer.state ) // => "resolved"

API

Deferred

Deferred Constructor.

const defer = new Deferred();

Properties

promise : Promise

Returns Promise.

defer.promise.then(...)

state : 'pending' | 'resolved' | 'rejected'

Returns current state.

isCompleted : boolean

Returns whether completed or not.

Methods

resolve(value: T)

Resolve promise.

reject(reason: any)

Reject promise.

License

MIT