promiscuous is a tiny implementation of the Promises/A+ spec.
It is promise library in JavaScript, small (< 1kb minified / < 0.6kb gzipped) and fast.
First, install promiscuous with npm.
$ npm install promiscuous
Then, include promiscuous in your code file.
var Promise = require('promiscuous');
Include promiscuous in your HTML file.
<script src="promicuous-browser.js"></script>
This version (and a minified one) can be built with:
$ build/build.js
var promise = Promise.resolve("one");
promise.then(function (value) { console.log(value); });
/* one */
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." */
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 */
var promises = [promiseLater(1), promiseLater(2), promiseLater(3)];
Promise.all(promises).then(function (values) { console.log(values); });
/* [1, 2, 3] */