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@workInProgress
@ngdoc overview
@name Tutorial: Step 2
@description
<table id="tutorial_nav">
<tr>
<td id="previous_step">{@link tutorial.step_1 Previous}</td>
<td id="step_result">{@link http://angular.github.com/angular-phonecat/step-2/app Example}</td>
<td id="tut_home">{@link tutorial Tutorial Home}</td>
<td id="code_diff">{@link
https://github.com/angular/angular-phonecat/commit/02e30dd64e0e5554fbf4d442ade5b1a251f2bf56
Code Diff}</td>
<td id="next_step">{@link tutorial.step_3 Next}</td>
</tr>
</table>
An important feature of angular is the incorporation of the principles behind {@link
http://en.wikipedia.org/wiki/Model–View–Controller the MVC design pattern} into client-side web
apps. With that in mind, let's use a little angular and a little JavaScript to add Model, View,
and Controller components to our app.
Our __View__ component is constructed by angular from this template:
__`app/index.html`:__
<pre>
...
<body ng:controller="PhoneListCtrl">
<ul>
<li ng:repeat="phone in phones">
{{phone.name}}
<p>{{phone.snippet}}</p>
</li>
</ul>
<script src="lib/angular/angular.js" ng:autobind></script>
<script src="js/controllers.js"></script>
</body>
...
</pre>
Our data __Model__ (a small set of phones in object literal notation) is instantiated within our
__Controller__ function (`PhoneListCtrl`):
__`app/js/controllers.js`:__
<pre>
/* App Controllers */
function PhoneListCtrl() {
this.phones = [{"name": "Nexus S",
"snippet": "Fast just got faster with Nexus S."},
{"name": "Motorola XOOM™ with Wi-Fi",
"snippet": "The Next, Next Generation tablet."},
{"name": "MOTOROLA XOOM™",
"snippet": "The Next, Next Generation tablet."}];
}
</pre>
The "Angular way" urges us to test as we develop:
__`test/unit/controllersSpec.js`:__
<pre>
/* jasmine specs for controllers go here */
describe('PhoneCat controllers', function() {
describe('PhoneListCtrl', function(){
it('should create "phones" model with 3 phones', function() {
var ctrl = new PhoneListCtrl();
expect(ctrl.phones.length).toBe(3);
});
});
});
</pre>
## Discussion:
So what were our changes from Step 1?
* __View template:__ We replaced the hard-coded phone list with the {@link
angular.widget.@ng:repeat ng:repeat widget} and two {@link guide.expression angular expressions}
enclosed in curly braces: `{{phone.name}}` and `{{phone.snippet}}`:
* The `ng:repeat="phone in phones"` statement in the `<li>` tag is an angular repeater. It
tells angular to create a `<li>` element for each phone in the phones list, using the first
`<li>` tag as the template.
* The curly braces around `phone.name` and `phone.snippet` are an example of {@link
angular.markup angular markup}. The curly braces are shorthand for the angular directive
{@link angular.directive.ng:bind ng:bind}. They indicate to angular that these are template
binding points. Binding points are locations in the template where angular constructs two-way
data-binding between the View and the Model. In angular, the View is a projection of the Model
through the HTML template.
* __Controller:__ At this point, it doesn't appear as if our controller is doing very much
controlling, but it is playing a crucial role: providing context for our data model so we can
establish two-way data-binding between the model and the view. Note in the following how we
connected the dots between our presentation, data, and logic components:
* The name of our controller function (in the JavaScript file `controllers.js`) matches the
{@link angular.directive.ng:controller ng:controller} directive in the `<body>` tag
(`PhoneListCtrl`).
* We instantiated our data within the scope of our controller function, and our template
binding points are located within the block bounded by the `<body
ng:controller="PhoneListCtrl>` tag.
So, our controller function becomes the {@link angular.scope scope} of our data model.
Angular uses scopes, along with the information contained in the template, data model, and
controller to keep the Model and View separated but in sync: any changes to the model are
reflected in the view; any changes that occur in the view are reflected in the model.
* __Model:__ For our data model, we created a simple array of phone records, specified in object
literal notation.
* __Testing:__ Ease of testing is another cornerstone of angular's design philosophy. All we are
doing here is showing how easy it is to create a unit test using the technology baked into
angular. The test verifies that we have some data, and that there are 3 records in the data set.
Angular's testing stack utilizes Jasmine's Behavior-driven Development (BDD) framework. You
can learn about it on the {@link http://pivotal.github.com/jasmine/ Jasmine home page} and on
the {@link https://github.com/pivotal/jasmine/wiki Jasmine wiki}.
<table id="tutorial_nav">
<tr>
<td id="previous_step">{@link tutorial.step_1 Previous}</td>
<td id="step_result">{@link http://angular.github.com/angular-phonecat/step-2/app Example}</td>
<td id="tut_home">{@link tutorial Tutorial Home}</td>
<td id="code_diff">{@link
https://github.com/angular/angular-phonecat/commit/02e30dd64e0e5554fbf4d442ade5b1a251f2bf56
Code Diff}</td>
<td id="next_step">{@link tutorial.step_3 Next}</td>
</tr>
</table>
|
