deep-aplus

deep-aplus

Resolve a whole structure of promises, library agnostic

This small library is a promise-library agnostic function that resolves a whole structure or objects, arrays, promises and values to a single promise in which the whole structure is resolved.

Unlike other libraries like q-deep, resolve-deep and swear, this library is designed to work without dependencies to any promise library (and also without any other dependencies). Just pass the promise constructor (i.e. Q.Promise or Promise) as first argument.

Note: There is no cycle check. You have to check for cycles yourself before passing the structure to the function

Installation

npm install deep-aplus

Usage

The following example demonstrates how to use this module:

var Q = require('q')
var deep = require('deep-aplus')(Q.Promise)

// Create a promise that returns a value (for demonstration purposes)
function P(value) {
  return Q.delay(1).then(function () {
    return value
  })
}

deep(2).then(console.log) // 2
  .then(() => deep(P(2)))
  .then(console.log) // 2

  .then(() => deep({a: 1, b: P(2)}))
  .then(console.log) // { a: 1, b: 2 }

  .then(() => deep({a: 1, b: [2, P(3)]}))
  .then(console.log) // { a: 1, b: [ 2, 3 ] }

  .then(() => deep({a: 1, b: {c: 2, d: P(3)}}))
  .then(console.log) // { a: 1, b: { c: 2, d: 3 } }

  // Nesting promises
  .then(() => deep({a: 1, b: P([2, P(3)])}))
  .then(console.log) // { a: 1, b: [ 2, 3 ] }

  .then(() => deep({a: 1, b: P([2, P(3)])}))
  .then(console.log) // { a: 1, b: [ 2, 3 ] }

  .then(() => deep({a: 1, b: P({c: 2, d: P(3)})}))
  .then(console.log) // { a: 1, b: { c: 2, d: 3 } }

  // does not dive into classes in order to preserve their functionality
  .then(() => {
    function A() {
      this.a = 2;
      this.b = P(3)
    }
    return deep(new A())
  })
  .then(console.log) // A { a: 2, b: { state: 'pending' } })

API-reference

index ⇒ function

Creates a deep(value)-function using the provided constructor to create the resulting promise and promises for intermediate steps. The deep function returns a promise for the resolution of an arbitrary structure passed as parameter

Returns: function - a function that returns a promise (of the provided class) for a whole object structure
Access: public

Param	Type	Description
Promise	function	class in which promises are created

License

deep-aplus is published under the MIT-license. See LICENSE.md for details.

Release-Notes

For release notes, see CHANGELOG.md

Contributing guidelines

See CONTRIBUTING.md.