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Defining a Component

To define a component, create a template whose name starts with components/. To define a new component, {{blog-post}} for example, create a components/blog-post template.

Note: Components must have a dash in their name. So blog-post is an acceptable name, but post is not. This prevents clashes with current or future HTML element names, and ensures Ember picks up the components automatically.

A sample component template would look like this:

app/templates/components/blog-post.hbs

<h1>Blog Post</h1>
<p>Lorem ipsum dolor sit amet.</p>

Having a template whose name starts with components/ creates a component of the same name. Given the above template, you can now use the {{blog-post}} custom element:

app/templates/index.hbs

{{#each model as |post|}}
  {{#blog-post title=post.title}}
    {{post.body}}
  {{/blog-post}}
{{/each}}

app/templates/components/blog-post.hbs

<article class="blog-post">
  <h1>{{title}}</h1>
  <p>{{yield}}</p>
  <p>Edit title: {{input type="text" value=title}}</p>
</article>

app/routes/index.js

var posts = [{
    title: "Rails is omakase",
    body: "There are lots of à la carte software environments in this world."
  }, {
    title: "Broken Promises",
    body: "James Coglan wrote a lengthy article about Promises in node.js."
}];

export default Ember.Route.extend({
  model: function() {
    return posts;
  }
});

app/components/blog-post.js

export default Ember.Component.extend({
});

Each component, under the hood, is backed by an element. By default Ember will use a <div> element to contain your component's template. To learn how to change the element Ember uses for your component, see Customizing a Component's Element.

Defining a Component Subclass

Often times, your components will just encapsulate certain snippets of Handlebars templates that you find yourself using over and over. In those cases, you do not need to write any JavaScript at all. Just define the Handlebars template as described above and use the component that is created.

If you need to customize the behavior of the component you'll need to define a subclass of Ember.Component. For example, you would need a custom subclass if you wanted to change a component's element, respond to actions from the component's template, or manually make changes to the component's element using JavaScript.

Ember knows which subclass powers a component based on its name. For example, if you have a component called blog-post, you would create a file at app/components/blog-post.js. If your component was called audio-player-controls, the file name would be at app/components/audio-player-controls.js

In other words, Ember will look for a class with the camelized name of the component, followed by Component.

Component Name	Component Class
`blog-post`	`App.BlogPostComponent`
`audio-player-controls`	`App.AudioPlayerControlsComponent`

Defining a Component Subclass