step_08.ngdoc

@ngdoc tutorial
@name 8 - Templating Links & Images
@step 8
@description

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In this step, we will add thumbnail images for the phones in the phone list, and links that, for
now, will go nowhere. In subsequent steps, we will use the links to display additional information
about the phones in the catalog.

* There are now links and images of the phones in the list.


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## Data

Note that the `phones.json` file contains unique IDs and image URLs for each of the phones. The
URLs point to the `app/img/phones/` directory.

<br />
**`app/phones/phones.json`** (sample snippet):

```json
[
  {
    ...
    "id": "motorola-defy-with-motoblur",
    "imageUrl": "img/phones/motorola-defy-with-motoblur.0.jpg",
    "name": "Motorola DEFY\u2122 with MOTOBLUR\u2122",
    ...
  },
  ...
]
```


## Component Template

<br />
**`app/phone-list/phone-list.template.html`:**

```html
...
<ul class="phones">
  <li ng-repeat="phone in $ctrl.phones | filter:$ctrl.query | orderBy:$ctrl.orderProp" class="thumbnail">
    <a href="#/phones/{{phone.id}}" class="thumb">
      <img ng-src="{{phone.imageUrl}}" alt="{{phone.name}}" />
    </a>
    <a href="#/phones/{{phone.id}}">{{phone.name}}</a>
    <p>{{phone.snippet}}</p>
  </li>
</ul>
...
```

To dynamically generate links that will in the future lead to phone detail pages, we used the
now-familiar double-curly brace binding in the `href` attribute values. In step 2, we added the
`{{phone.name}}` binding as the element content. In this step the `{{phone.id}}` binding is used in
the element attribute.

We also added phone images next to each record using an image tag with the {@link ngSrc ngSrc}
directive. That directive prevents the browser from treating the AngularJS `{{ expression }}` markup
literally, and initiating a request to an invalid URL (`http://localhost:8000/{{phone.imageUrl}}`),
which it would have done if we had only specified an attribute binding in a regular `src` attribute
(`<img src="{{phone.imageUrl}}">`). Using the `ngSrc` directive, prevents the browser from making an
HTTP request to an invalid location.


# Testing

<br />
**`e2e-tests/scenarios.js`**:

```js
    ...

    it('should render phone specific links', function() {
      var query = element(by.model('$ctrl.query'));
      query.sendKeys('nexus');

      element.all(by.css('.phones li a')).first().click();
      expect(browser.getCurrentUrl()).toBe('/phones/nexus-s');
    });

    ...
```

We added a new E2E test to verify that the application is generating correct links to the phone
views, that we will implement in the upcoming steps.

You can now rerun `npm run protractor` to see the tests run.


# Experiments

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* Replace the `ngSrc` directive with a plain old `src` attribute. Using tools such as your browser's
  developer tools or inspecting the web server access logs, confirm that the application is indeed
  making an extraneous request to `%7B%7Bphone.imageUrl%7D%7D` (or `{{phone.imageUrl}}`).

  The issue here is that the browser will fire a request for that invalid image address as soon as
  it hits the `<img>` tag, which is before AngularJS has a chance to evaluate the expression and
  inject the valid address.


# Summary

Now that you have added phone images and links, go to {@link step_09 step 9} to learn about AngularJS
layout templates and how AngularJS makes it easy to create applications that have multiple views.


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