Amber.js

Amber.js (formerly SproutCore 2.0) is a JavaScript framework that does all of the heavy lifting that you'd normally have to do by hand. There are tasks that are common to every web app; Amber.js does those things for you, so you can focus on building killer features and UI.

These are the three features that make Amber.js a joy to use:

Bindings
Computed properties
Auto-updating templates

Amber.js has strong roots in SproutCore; you can read more about its evolution in the Amber.js launch announcement.

Bindings

Use bindings to keep properties between two different objects in sync. You just declare a binding once, and Amber.js will make sure changes get propagated in either direction.

Here's how you create a binding between two objects:

MyApp.president = SC.Object.create({
  name: "Barack Obama"
});

MyApp.country = SC.Object.create({
  // Ending a property with 'Binding' tells Amber.js to
  // create a binding to the presidentName property.
  presidentNameBinding: 'MyApp.president.name'
});

MyApp.country.get('presidentName');
// "Barack Obama"

Bindings allow you to architect your application using the MVC (Model-View-Controller) pattern, then rest easy knowing that data will always flow correctly from layer to layer.

Computed Properties

Computed properties allow you to treat a function like a property:

MyApp.president = SC.Object.create({
  firstName: "Barack",
  lastName: "Obama",

  fullName: function() {
    return this.get('firstName') + ' ' + this.get('lastName');

    // Call this flag to mark the function as a property
  }.property()
});

MyApp.president.get('fullName');
// "Barack Obama"

Treating a function like a property is useful because they can work with bindings, just like any other property.

Many computed properties have dependencies on other properties. For example, in the above example, the fullName property depends on firstName and lastName to determine its value. You can tell Amber.js about these dependencies like this:

MyApp.president = SC.Object.create({
  firstName: "Barack",
  lastName: "Obama",

  fullName: function() {
    return this.get('firstName') + ' ' + this.get('lastName');

    // Tell Amber.js that this computed property depends on firstName
    // and lastName
  }.property('firstName', 'lastName')
});

Make sure you list these dependencies so Amber.js knows when to update bindings that connect to a computed property.

Auto-updating Templates

Amber.js uses Handlebars, a semantic templating library. To take data from your JavaScript application and put it into the DOM, create a <script> tag and put it into your HTML, wherever you'd like the value to appear:

<script type="text/x-handlebars">
  The President of the United States is {{MyApp.president.fullName}}.
</script>

Here's the best part: templates are bindings-aware. That means that if you ever change the value of the property that you told us to display, we'll update it for you automatically. And because you've specified dependencies, changes to those properties are reflected as well.

Hopefully you can see how all three of these powerful tools work together: start with some primitive properties, then start building up more sophisticated properties and their dependencies using computed properties. Once you've described the data, you only have to say how it gets displayed once, and Amber.js takes care of the rest. It doesn't matter how the underlying data changes, whether from an XHR request or the user performing an action; your user interface always stays up-to-date. This eliminates entire categories of edge cases that developers struggle with every day.

Getting Started

For new users, we recommend downloading the Amber.js Starter Kit, which includes everything you need to get started.

We also recommend that you check out the annotated Todos example, which shows you the best practices for architecting an MVC-based web application. You can also browse or fork the code on Github.

Guides are available for Amber.js. If you find an error, please fork the guides on GitHub and submit a pull request. (Note that Amber.js guides are on the v2.0 branch.)

Building Amber.js

Run rake to build Amber.js. Two builds will be placed in the dist/ directory.

amber.js and amber.min.js - unminified and minified builds of Amber.js

If you are building under Linux, you will need a JavaScript runtime for minification. You can either install nodejs or gem install therubyracer.

How to Run Unit Tests

Install Ruby 1.9.2. There are many resources on the web can help; one of the best is rvm.
Run gem install bpm --pre to install bpm, the browser package manager.
To start the development server, run bpm preview.
Then visit: http://localhost:4020/assets/spade-qunit/index.html?package=PACKAGE_NAME. Replace PACKAGE_NAME with the name of the package you want to run. For example:

To run multiple packages, you can separate them with commas. For example, to run all of the unit tests together:

http://localhost:4020/assets/spade-qunit/index.html?package=sproutcore-metal,sproutcore-runtime,sproutcore-views,sproutcore-handlebars

Adding New Packages

Be sure you include the new package as a dependency in the global package.json.

davebalmer/amber.js