86 lines
3.6 KiB
Markdown
86 lines
3.6 KiB
Markdown
{@a top}
|
|
|
|
# Set the Document Title
|
|
|
|
Your app should be able to make the browser title bar say whatever you want it to say.
|
|
This cookbook explains how to do it.
|
|
|
|
See the <live-example name="set-document-title"></live-example>.
|
|
|
|
<div class="l-sub-section">
|
|
<img src='generated/images/plunker/plunker-switch-to-editor-button.png'alt="pop out the window" class="right">
|
|
<img src='generated/images/plunker/plunker-separate-window-button.png' alt="pop out the window" class="right">
|
|
|
|
To see the browser title bar change in the live example,
|
|
open it again in the Plunker editor by clicking the icon in the upper right,
|
|
then pop out the preview window by clicking the blue 'X' button in the upper right corner.
|
|
|
|
</div>
|
|
|
|
## The problem with *<title>*
|
|
|
|
The obvious approach is to bind a property of the component to the HTML `<title>` like this:
|
|
|
|
<code-example format=''>
|
|
<title>{{This_Does_Not_Work}}</title>
|
|
</code-example>
|
|
|
|
Sorry but that won't work.
|
|
The root component of the application is an element contained within the `<body>` tag.
|
|
The HTML `<title>` is in the document `<head>`, outside the body, making it inaccessible to Angular data binding.
|
|
|
|
You could grab the browser `document` object and set the title manually.
|
|
That's dirty and undermines your chances of running the app outside of a browser someday.
|
|
|
|
<div class="l-sub-section">
|
|
|
|
Running your app outside a browser means that you can take advantage of server-side
|
|
pre-rendering for near-instant first app render times and for SEO. It means you could run from
|
|
inside a Web Worker to improve your app's responsiveness by using multiple threads. And it
|
|
means that you could run your app inside Electron.js or Windows Universal to deliver it to the desktop.
|
|
|
|
</div>
|
|
|
|
## Use the `Title` service
|
|
|
|
Fortunately, Angular bridges the gap by providing a `Title` service as part of the *Browser platform*.
|
|
The [Title](api/platform-browser/Title) service is a simple class that provides an API
|
|
for getting and setting the current HTML document title:
|
|
|
|
* `getTitle() : string`—Gets the title of the current HTML document.
|
|
* `setTitle( newTitle : string )`—Sets the title of the current HTML document.
|
|
|
|
You can inject the `Title` service into the root `AppComponent` and expose a bindable `setTitle` method that calls it:
|
|
|
|
|
|
<code-example path="set-document-title/src/app/app.component.ts" region="class" title="src/app/app.component.ts (class)" linenums="false"></code-example>
|
|
|
|
Bind that method to three anchor tags and voilà!
|
|
|
|
<figure>
|
|
<img src="generated/images/guide/set-document-title/set-title-anim.gif" alt="Set title">
|
|
</figure>
|
|
|
|
Here's the complete solution:
|
|
|
|
<code-tabs>
|
|
<code-pane title="src/main.ts" path="set-document-title/src/main.ts"></code-pane>
|
|
<code-pane title="src/app/app.module.ts" path="set-document-title/src/app/app.module.ts"></code-pane>
|
|
<code-pane title="src/app/app.component.ts" path="set-document-title/src/app/app.component.ts"></code-pane>
|
|
</code-tabs>
|
|
|
|
## Why provide the `Title` service in `bootstrap`
|
|
|
|
Generally you want to provide application-wide services in the root application component, `AppComponent`.
|
|
|
|
This cookbook recommends registering the title service during bootstrapping,
|
|
a location you reserve for configuring the runtime Angular environment.
|
|
|
|
That's exactly what you're doing.
|
|
The `Title` service is part of the Angular *browser platform*.
|
|
If you bootstrap your application into a different platform,
|
|
you'll have to provide a different `Title` service that understands
|
|
the concept of a "document title" for that specific platform.
|
|
Ideally, the application itself neither knows nor cares about the runtime environment.
|
|
|