promiscuous-umd v0.7.3

promiscuous-umd

promiscuous-umd is a tiny-ish implementation of the Promises/A+ spec.

It is promise library in JavaScript, small (< 1.5kb minified / < 0.75kb gzipped) and fast.

Forked from promiscuous, it trades an additional 0.5kb over the original library to provide a singular package compatible with all platforms and module loaders, including a shim to check if a native Promise is already provided, since it's 2017 and most browsers include them now.

Installation and usage

Node

First, install promiscuous with npm.

$ npm install promiscuous-umd

Then, include promiscuous in your code file.

var Promise = require('promiscuous-umd');

Browsers

Include in your HTML file, or via a your favorite module loader:

<script src="promiscuous-umd.js"></script>

//RequireJS
require( ['promiscuous-umd'],function (Promise) {
  var p = new Promise(function(resolve,reject){})
})
//CommonJS / Webpack
var Promise = require('promiscuous-umd');

A minified version is built on install (dist/promiscuous-min.js), but can be re-built with:

$ build/build.js

API

Create a resolved promise

var promise = Promise.resolve("one");
promise.then(function (value) { console.log(value); });
/* one */

Create a rejected promise

var brokenPromise = Promise.reject(new Error("Could not keep promise."));
brokenPromise.then(null, function (error) { console.error(error.message); });
/* "Could not keep promise." */

You can also use the catch method if there is no success callback:

brokenPromise.catch(function (error) { console.error(error.message); });
/* "Could not keep promise." */

Write a function that returns a promise

function promiseLater(something) {
  return new Promise(function (resolve, reject) {
    setTimeout(function () {
      if (something)
        resolve(something);
      else
        reject(new Error("nothing"));
    }, 1000);
  });
}
promiseLater("something").then(
  function (value) { console.log(value); },
  function (error) { console.error(error.message); });
/* something */

promiseLater(null).then(
  function (value) { console.log(value); },
  function (error) { console.error(error.message); });
/* nothing */

Convert an array of promises into a promise for an array

var promises = [promiseLater(1), promiseLater(2), promiseLater(3)];
Promise.all(promises).then(function (values) { console.log(values); });
/* [1, 2, 3] */