Deferred

A lightweight implementation of Deferred/Promise.

Installation

Node

$ npm install deferred-lib

Browser

<script src="js/deferred.min.js"></script>

Usage

// Usage 1
// Declare the deferred instance and use it.
function countdown1() {
    var deferred = new Deferred();
    var i = 5;
    var timer = setInterval(function () {
        deferred.notify(i);
        if (i-- === 0) {
            deferred.resolve('Hi');
            clearInterval(timer);
        }
    }, 300);
    return deferred.promise();
}

countdown1().progress(function (step) {
    console.log('countdown1', step);
}).done(function () {
    console.log('countdown1 done');
});


// Usage 2
// Use `Deferred(fn)` and get the deferred instance with `this` context.
function countdown2() {
    var self = this;
    var i = 5;
    var timer = setInterval(function () {
        self.notify(i);
        if (i-- === 0) {
            self.resolve('Hi');
            clearInterval(timer);
        }
    }, 300);
}

Deferred(countdown2).progress(function (step) {
    console.log('countdown2', step);
}).done(function () {
    console.log('countdown2 done');
});

See examples directory for more usages.