Why use the Nx CLI?
The Nx CLI isn't like most command lines that accomplishes a predefined task. Nx can be configured to work with different tools and even different languages.
Nrwl and the community have created plugins that provide a base level of functionality. In addition, your organization can further customize what Nx does to fit your needs.
Nx allows you to break up your codebase into different projects. The Nx CLI provides commands to operate and manage the different parts of the codebase. These commands fall into three categories:
- Acting on code (Build, Test, Serve)
- Modifying code
- Understanding the codebase
nx help command to see a full list of commands in the Nx CLI.
Acting on Code
Each project can be configured with targets that can be executed on the source code of the project.
nx run command executes a target on a single project. For convenience, you can also run
nx [target] [project] which is an alias to
nx run [project]:[target].
nx run my-react-app:build nx build my-react-app
Nx also automatically caches the output of running targets so re-running the same target on the same project source code will be instant.
nx build is only an abstraction over what it means to "build" projects rather than tied to a certain implementation. Each target's has an executor which actually defines how to execute target on a project. You can change the executor or write an entirely custom one to fit your needs.
Along with running a target on a single project, Nx provides some commands to run the same target across multiple projects.
nx run-many command runs the same target name across a list of projects.
nx run-many --target build --projects app1,app2 nx run-many --target test --all # Runs all projects that have a test target, use this sparingly.
nx affected command isolates set projects that may have changed in behavior and runs a target across them. This is more efficient than running all projects every time.
nx affected --target build
nx generate command generates and modifies code.
nx generate app my-react-app nx generate @nrwl/react:lib shared-button nx generate @nrwl/react:storybook-configuration shared-button # Configures storybook for a UI library
nx generate is only an abstraction over generating code.
nx generate can generate anything you want via generators. Generators can be installed as part of a plugin or developed locally within an Nx workspace to fit the needs of your organization.
A Workspace Generator is custom generator for your workspace.
nx generate workspace-generator my-generator generates a workspace generator which can be run with the
nx workspace-generator command. This can be useful to allow your organization to consistently generate projects according to your own standards.
nx workspace-generator my-generator
Upgrading a package is not always as simple as bumping the version in
nx migrate command facilitates not only managing package versions but also runs migrations specified by package mantainers. See the full guide to updating Nx.
nx migrate latest # Updates the version of Nx in `package.json` and schedules migrations to be run nx migrate --run-migrations # Runs the migrations scheduled by the previous command.
Understanding the codebase
Nx creates and maintains a dependency graph between projects based on import statements in your code and uses that information to run executors only on the affected projects in a codebase. A visual version of the dependency graph is also available to help developers understand the architecture of the codebase.
nx dep-graph command displays this dependency graph in a web browser for you to explore.
nx dep-graph nx dep-graph --watch # Updates the browser as code is changed nx affected:dep-graph # Highlights projects which may have changed in behavior
nx list command lists the currently installed Nx plugins and other available plugins. The
nx list command can list the generators and executors that are available for a plugin.
List installed plugins:
nx list nx list @nrwl/react # Lists capabilities in the @nrwl/react plugin
Common Environment Variables
There are some environment variables that you can set to log additional information from Nx.
- Setting NX_VERBOSE_LOGGING=true will print debug information useful for troubleshooting.
- Setting NX_PERF_LOGGING=true will print debug information useful for profiling executors and Nx itself.