As Provided vs. Derived Generator Path Options

Nx is moving toward a more transparent and predictable way of determining where code will be generated when you run a generator. The new behavior is to take generator options as provided and place the generated code in the exact folder that you specify. Nx will only use the new behavior in Nx version 19. The directory can be specified with a --directory flag or use a fully specified path (i.e. libs/shared/my-lib/src/my-component). The --directory flag will be calculated relative to where you run the command.

In the past, Nx had lots of logic to try and derive the best place to put code for you. This approach worked for some people, but there were always people that wanted to generate their code in a slightly different location. Accounting for these variations lead to either (1) people in repos with a different structure not being able to use these generators or (2) Nx introducing lots of flags to allow people to tweak where code was generated (flags like --project, --flat, --pascalCaseFiles, --pascalCaseDirectory, --fileName). It also caused some confusion when code was not generated in the expected location or frustration when the user did not know how to get Nx to derive the right thing.

Here are some of the issues with the derived behavior that are addressed with as-provided:

• Some generators had multiple flags for the same thing: directory, path, etc. Going forward, we only use --directory across all generators.
• Generators resolved the directory option inconsistently. Some resolved it relative to the workspace root while others resolved it relative to the project's source root. In the future, all generators will resolve the directory option relative to the current working directory. As such, your terminal's path autocomplete will work as expected and you can also cd right into the directory you want.
• Nx transformed the provided names to kebab-case. In the future, the name will be taken as provided. This allows for users to deviate from the kebab-case directory structure. Nx also included the directory in the project name, which lead to verbose names such as products-product-detail-page. Now that Nx takes options as provided, names will be as simple as you would like. You can keep it simple for feature projects (.e.g. home-page), or name libraries based on their import path like @my-org/design-system/buttons. You can do a mix of both, or deviate from this completely. Note that projects still need to have unique names so you might encounter an error when the name you provide is not valid, but you can resolve the conflict however suits your workspace best.

Using Nx Console

You can use Nx Console for an intuitive experience running generators.

1. If you right-click a folder and choose Nx generate, the code generation will be run from that folder.
2. As you fill out the generate form, Nx Console will show you a preview of where the new files will be generated.

Prompting

To mitigate the impact of this change of direction, Nx will prompt you when running most generators until Nx 19. We know changing these habits may take time so this prompt allows you to choose the previous behavior.

There are two different kinds of generators that will prompt you to choose between as-provided and derived:

• Project Generators (applications and libraries)
• Other Code Generators (components and other code)

Your intent is your intent. However, the commands you write and run are based on how you think Nx will act. Nx used to derive the location of your code, but Nx will not in the future. In the future for the reasons stated above, Nx will only take options as provided so you should no longer expect Nx to derive the location. We know it will take time to get used to the new way Nx calculates generated code paths and names.

Project Generators

As of Nx 16.8.0, generating a project will prompt you to choose how Nx will calculate where the project should be located. For now, you can choose between as-provided and derived but as-provided will be the only option in Nx 19. The CLI flag to choose between the two algorithms for project generators is --projectNameAndRootFormat.

Generate Paths and Names as-provided

This setting makes app or lib generators behave in the following way:

• nx g app my-app creates a new application named my-app in the /my-app folder
• nx g lib my-lib creates a new library named my-lib in the /my-lib folder
• cd apps/nested/my-app && nx g app my-app creates a new application named my-app in the /apps/nested/my-app folder
• nx g app my-app --directory=apps/nested/my-app creates a new application named my-app in the /apps/nested/my-app folder
• nx g lib my-lib --directory=libs/shared/ui/my-lib creates a new library named my-lib in the /libs/shared/ui/my-lib folder

Use the Old derived Paths and Names

Choosing derived makes Nx behave the way it did before version 16.8.0. Nx will check the workspaceLayout property in nx.json to determine how it should calculate the path to the new project.

These settings would store apps in /demos/ and libraries in /packages/. The paths specified are relative to the workspace root.

This makes app or lib generators behave in the following way:

• nx g app my-app creates a new application named my-app in the /demos/my-app folder
• nx g lib my-lib creates a new library named my-lib in the /packages/my-lib folder
• nx g app my-app --directory=nested creates a new application named nested-my-app in the /demos/nested/my-app folder
• nx g lib my-lib --directory=shared/ui creates a new library named shared-ui-my-lib in the /packages/shared/ui/my-lib folder

If you accidentally generate a project in the wrong folder, use the move generator to move it to the correct location.

Code Generators

As of Nx 17, code generators such as component, service, and others will prompt you to choose whether or not Nx will derive the location based on your options or not. In Nx 19, Nx will take the generator options as provided. The following flags are deprecated and will be removed in Nx 19: --project, --flat, --pascalCaseFiles, --pascalCaseDirectory, --fileName. The CLI flag to choose between the two algorithms for code generators is --nameAndDirectoryFormat.

Generate Paths and Names as-provided

This setting makes generators behave in the following way:

• nx g component my-component creates a component in the root.
• cd apps/nested/my-app && nx g component my-component creates a new component named my-component in the /apps/nested/my-app folder
• nx g component my-component --directory=apps/nested/my-app creates a new component named my-component in the /apps/nested/my-app folder
• nx g component apps/nested/my-app/my-component creates a new component named my-component in the /apps/nested/my-app folder

Use the Old derived Paths and Names

Choosing derived makes Nx behave the way it did before version 17. Nx will use the deprecated flags (--project, --flat, --pascalCaseFiles, --pascalCaseDirectory, --fileName) to calculate where to generate the code. This behavior will not be available in Nx 19.

This makes generators behave in the following way:

• nx g component my-component creates a component in the default project.
• nx g component my-component --project=my-app creates a new component named my-component in the /apps/nested/my-app folder
• nx g component apps/nested/my-app/my-component creates a new component named my-component in the /apps/nested/my-app folder

Writing Scripts

If you are using nx generate in a script or another environment where it cannot have an interactive prompt, the command will still behave as it did before. You should opt into the new behavior and change the command with a command line flag.