angular-cn/aio/content/guide/prerendering.md

Prerendering static pages

Angular Universal allows you to prerender the pages of your application. Prerendering is the process where a dynamic page is processed at build time generating static HTML.

How to prerender a page

To prerender a static page make sure to add SSR capabilities to your application. For more information see the universal guide. Once SSR is added, run the following command:

npm run prerender

Build options for prerendering

When you add prerendering to your application, the following build options are available:

• browserTarget: Specify the target to build.
• serverTarget: Specify the Server target to use for prerendering the application.
• routes: Define an array of additional routes to prerender.
• guessRoutes: Whether builder should extract routes and guess which paths to render. Defaults to true.
• routesFile: Specify a file that contains a list of all routes to prerender, separated by newlines. This option is useful if you have a large number of routes.
• numProcesses: Specify the number of CPUs to be used while running the prerendering command.

Prerendering dynamic routes

You can prerender dynamic routes. An example of a dynamic route is product/:id, where id is dynamically provided.

To prerender dynamic routes, choose one from the following options:

• Provide additional routes in the command line
• Provide routes using a file
• Prerender specific routes

Provide additional routes in the command line

While running the prerender command, you can provide additional routes. For example:

ng run <app-name>:prerender --routes /product/1 /product/2

Providing additonal routes using a file

You can provide routes using a file to generate static pages. This method is useful if you have a large number of routes to generate, such as product details for an e-commerce application, which may come from an external source (Database or CMS).

To provide routes using a file, use the --routes-file option with the name of a .txt file containing the routes.

For example, you could generate this file by using a script to extract IDs from a database and save them to a routes.txt file:

/products/1 /products/555

When your .txt file is ready, run the following command to prerender the static files with dynamic values:

ng run <app-name>:prerender --routes-file routes.txt

Prerendering specific routes

You can also pass specific routes to the prerender command. If you choose this option, make sure to disable the guessRoutes option.

ng run <app-name>:prerender --no-guess-routes --routes /product/1 /product/1