cgx-promise

This is a minimal implementation of a Promise in Javascript.

NOTE: this library is deprecated. You should use the native Promise bundled with the browser.

Why using this library?

It's simple: because it weights 262 bytes compressed.

If you're looking for a Promise library with lots of functionalities, you are in the wrong place. However, if you need just a simple Promise library and don't want to add several kilobytes to your already big enough bundle, then this is it.

Installation

Bower

bower install cgx-promise

Usage

function myAsyncFunc() {
    const promise = new Promise();

    someAsyncCode((err, data) => {
        if (err) {
            promise.reject(err);
            return;
        }

        promise.resolve(data);
    })

    return promise;
}


myAsyncFunc()
    .then(data => console.log(data))
    .catch(err => console.log('An error occurred:', err));

What does this library supports?

Multiple then() which will be executed in the same order they are declared.
The catch() method will catch any call to reject() or any exception raised by a then().
Methods are chainable like in the example above.
The value returned by a then() will be the first argument for the next then().
Shared context for all then(). That is, if you store something in the "this" reference in a then(), it will be available next then().

FAQ

Why isn't this library available for node.js?

Well, this library is designed not to be fully-featured just to save space, which is a really valuable asset in front-end web development. However, if you are working with node.js, then you don't have to download the libraries each time you execute the code or each time a new request arrives. Therefore, since you don't have that restriction, I would advice you to use a full-featured promise library instead.

Sugestions & feature requests

If you have any suggestions on how to improve this library or a feature that you consider should be part of this library, please create a new issue to discuss it. If we decide that it should be part of the library, I will gladly implement it.

ngonzalvez/cgx-promise