/promise

Promises/A+

Spec of common, standardised behaviour https://promisesaplus.com/

Notes:

Events are great for things that can happen multiple times on the same object — keyup, touchstart etc. async success/failure A promise can only succeed or fail once. It cannot succeed or fail twice, neither can it switch from success to failure or vice versa If a promise has succeeded or failed and you later add a success/failure callback, the correct callback will be called, even though the event took place earlier

A promise can be:

fulfilled The action relating to the promise succeeded rejected The action relating to the promise failed pending Hasn't fulfilled or rejected yet settled Has fulfilled or rejected

thenable: object that is promise-like, with a then method

Promises/A+: common, standardised behaviour (spec)

must not change means immutable identity (i.e. ===), but does not imply deep immutability.

Promise implementations

Promise API

RSVP

  • promise.js

  • /Promise

    • all.js
    • race.js
    • reject.js
    • resolve.js

  • events.js

    • mixin
    • on
    • off
    • trigger

  • config.js

    • EventTarget'mixin'; //extends config object with EventTarget methods

  • utils.js

    • Array.isArray(obj) // Little known fact: Array.prototype itself is an array
    • Using Polyfill Object.prototype.toString.call(x) to detect object class
      • [object Date]
      • [object String]
      • [object Math]
      • [object Undefined] // Since JavaScript 1.8.5
      • [object Null] // Since JavaScript 1.8.5

  • instrument.js

    • instrument(): scheduleFlush() when first queue memeber is stored.

  • -internal.js

    • new TypeError([message[, fileName[, lineNumber]]])
    • Define CONSTANT value: PENDING (0), FULFILLED (1), REJECTED (2)
    • [Spec]: throw error is then function is not available for Promise
    • getThen()
    • tryThen()

  • node.js

    • getThen()
    • tryApply(f, s, a)
    • wrapThenable(then, promise)

  • race.js

  • enumerator.js