angular-cn/aio/content/guide/app-shell.md

App shell

应用外壳

App shell is a way to render a portion of your application via a route at build time. It can improve the user experience by quickly launching a static rendered page (a skeleton common to all pages) while the browser downloads the full client version and switches to it automatically after the code loads.

应用外壳是一种在构建期间借助路由渲染部分应用的方法。它可以通过快速启动一个静态渲染页面（所有页面的公共骨架）来改善用户体验。与此同时，浏览器会下载完整的客户端版本，并在代码加载后自动切换到完整版。

This gives users a meaningful first paint of your application that appears quickly because the browser can simply render the HTML and CSS without the need to initialize any JavaScript.

这能让用户快速看到应用中第一个有意义的画面，因为浏览器可以很简单地渲染出 HTML 和 CSS，而无需初始化任何 JavaScript。

Learn more in The App Shell Model.

欲知详情，参见应用外壳模型。

Step 1: Prepare the application

第 1 步：准备本应用

You can do this with the following CLI command:

可以用下列 CLI 命令来执行本操作：

ng new my-app --routing

For an existing application, you have to manually add the RouterModule and defining a <router-outlet> within your application.

对于既有应用，你必须手动添加 RouterModule 并在应用中定义 <router-outlet> 。

Step 2: Create the app shell

第 2 步：创建应用外壳

Use the CLI to automatically create the app shell.

使用 CLI 自动创建一个应用外壳。

ng generate app-shell --client-project my-app --universal-project server-app

• my-app takes the name of your client application.

  my-app 是本客户端应用的名字。

• server-app takes the name of the Universal (or server) application.

  server-app 是这个 Universal（或 server）应用的名字。

After running this command you will notice that the angular.json configuration file has been updated to add two new targets, with a few other changes.

执行完这个命令，你会发现 angular.json 配置文件中已经增加了两个新目标，并做了一些其它更改。

"server": { "builder": "@angular-devkit/build-angular:server", "options": { "outputPath": "dist/my-app-server", "main": "src/main.server.ts", "tsConfig": "tsconfig.server.json" } }, "app-shell": { "builder": "@angular-devkit/build-angular:app-shell", "options": { "browserTarget": "my-app:build", "serverTarget": "my-app:server", "route": "shell" } }

Step 3: Verify the app is built with the shell content

第 3 步：验证该应用是使用应用外壳的内容构建的

Use the CLI to build the app-shell target.

使用 CLI 构建目标 app-shell。

ng run my-app:app-shell

To verify the build output, open dist/my-app/index.html. Look for default text app-shell works! to show that the app shell route was rendered as part of the output.

要验证构建的输出，请打开 dist/my-app/index.html。寻找默认的文本 app-shell works! 就可以验证这个应用外壳路由确实是作为输出的一部分渲染出来的。