lie is a small, performant promise library implementing the Promises/A+ spec (Version 1.1).

Originally a fork of Ruben Verborgh's promiscuous, with version 2.6 it became a fork of ayepromise by Chris Burgmer.

npm install lie

var Promise = require('lie');
// or use the pollyfill
require('lie/polyfill');

Either use it with browserify (recommended) or grab one of the files from the dist folder:

• lie.js/lie.min.js exposes 'Promise' either as a UMD module or from the global scope, depending on if a CJS or AMD loader is available.
• lie.polyfill.js/lie.polyfill.min.js adds 'Promise' to the global scope only if it's not already defined (not a UMD).

Implements the standard ES6 api:

new Promise(function(resolve, reject){
    doSomething(function(err, result) {
        if (err) {
            reject(err);
        } else {
            resolve(result);
        }
    });
}).then(function (value) {
    //on success
}, function (reason) {
    //on error
}).catch(function (reason) {
    //shortcut for error handling
});

Promise.all([
    //array of promises or values
]).then(function ([/* array of results */]));

Promise.race([
    //array of promises or values
]);
// either resolves or rejects depending on the first value to do so

In Node.js, lie emits an unhandledRejection event when a rejected promise isn't caught, in line with how io.js does it. This allows it to act as a promise shim in both Node.js and the browser.