promises.js

// EXAMPLE 1
var promise = new WinJS.Promise(function (completeCallback, errorCallback) {
    // do some async operation
    // if completed properly, call completeCallback()
    // otherwise call errorCallback(error)
});


//EXAMPLE 2
// extenally managed promise
var complete;
var error;
var promise = new WinJS.Promise(function (completeCallback, errorCallback) {
    complete = completeCallback;
    error = errorCallback;
});


// do some async operation
// if completed properly, call complete() => which completes the promise
// otherwise call error(error) => which errors the promise