promise-example.js

// Promise to be filled with future value
var futureValue = new Promise();

// .then() will return a new promise
var anotherFutureValue = futureValue.then();

// Promise state handlers ( must be a function ).
// The returned value of the fulfilled / failed handler will be the value of the promise.
futureValue.then({

    // Called if/when the promise is fulfilled
    fulfilledHandler: function() {},

    // Called if/when the promise fails
    errorHandler: function() {},

    // Called for progress events (not all implementations of promises have this)
    progressHandler: function() {}
});