Next.js CLI

Next.js CLI 帮你启动、构建和导出（export）应用程序。

要列出所有可用的 CLI 命令，请在项目目录中运行以下命令：

npx next -h

(npx 随 npm 5.2+ 或更高版本一同分发)

输出如下所示：

Usage
  $ next <command>

Available commands
  build, start, export, dev, lint, telemetry

Options
  --version, -v   Version number
  --help, -h      Displays this message

For more information run a command with the --help flag
  $ next build --help

你可以将任何 node 参数 传递给 next 命令：

NODE_OPTIONS='--throw-deprecation' next
NODE_OPTIONS='-r esm' next
NODE_OPTIONS='--inspect' next

构建

next build 将为你的应用程序构建一个creates an optimized production build of your application. The output displays information about each route.

• Size – The number of assets downloaded when navigating to the page client-side. The size for each route only includes its dependencies.
• First Load JS – The number of assets downloaded when visiting the page from the server. The amount of JS shared by all is shown as a separate metric.

The first load is indicated by green, yellow, or red. Aim for green for performant applications.

你可以在执行 next build 时使用 --profile 标记来开启 React 的with theflag in. This requires Next.js 9.5:

next build --profile

之后，你可以 you can use the profiler in the same way as you would in development.

You can enable more verbose build output with the --debug flag in next build. This requires Next.js 9.5.3:

next build --debug

With this flag enabled additional build output like rewrites, redirects, and headers will be shown.

Development 模式

next dev 在 development 模式下启动应用程序，并且starts the application in development mode with hot-code reloading, error reporting, and more:

默认情况下，该应用程序可以通过 http://localhost:3000 地址访问。通过 -p 参数可以修改默认端口号，例如：

npx next dev -p 4000

Or using the PORT environment variable:

PORT=4000 npx next dev

Note: PORT can not be set in .env as booting up the HTTP server happens before any other code is initialized.

You can also set the hostname to be different from the default of 0.0.0.0, this can be useful for making the application available for other devices on the network. The default hostname can be changed with -H, like so:

npx next dev -H 192.168.1.2

Production 模式

next start 也在 production 模式下启动应用程序。该应用程序应该首先通过 next build 命令进行编译。

默认情况下，该应用程序可以通过 http://localhost:3000 地址访问。通过 -p 参数可以修改默认端口号，例如：

npx next start -p 4000

Or using the PORT environment variable:

PORT=4000 npx next start

Note: PORT can not be set in .env as booting up the HTTP server happens before any other code is initialized.

Lint

next lint runs ESLint for all files in the pages, components, and lib directories. It also provides a guided setup to install any required dependencies if ESLint is not already configured in your application.

If you have other directories that you would like to lint, you can specify them using the --dir flag:

next lint --dir utils

遥测

Next.js 收集有关常规使用下的 完全匿名 的遥测数据。 此匿名计划并非强制参与，如果你不想共享任何信息，则可以选择退出。

有关遥测的更多信息，请阅读此文档。