Overview of the Nx JS Plugin

The JS plugin contains executors and generators that are useful for JavaScript/TypeScript projects in an Nx workspace.

Setting Up @nx/js

Installation

Keep Nx Package Versions In Sync

Make sure to install the @nx/js version that matches the version of nx in your repository. If the version numbers get out of sync, you can encounter some difficult to debug errors. You can fix Nx version mismatches with this recipe.

In any Nx workspace, you can install @nx/js by running the following command:

nx add @nx/js

This will install the correct version of @nx/js.

ts Preset

When initializing a new Nx workspace, specifying --preset=ts will generate a workspace with @nx/js pre-installed.

npm

npx create-nx-workspace my-org --preset=ts

yarn

yarn create nx-workspace my-org --preset=ts

Modernized monorepo setup

Nx 20 updates the TS monorepo setup when using --preset=ts. The workspace is set up with TypeScript Project References along with the Workspaces feature from npm, yarn, pnpm, and bun.

To create with the older setup for TS monorepo with compilerOptions.paths, use create-nx-workspace --preset=apps.

How @nx/js Infers Tasks

The @nx/js/typescript plugin will add a typecheck task to projects that have a tsconfig.json.

This plugin adds a build task for projects that:

1. Have a runtime tsconfig file (defaults to tsconfig.lib.json).
2. Have a package.json file containing entry points that are not source files.

For example, this project is buildable and will have a build task.

packages/pkg1/package.json

{
  "name": "@acme/pkg1",
  "exports": {
    "./package.json": "./package.json",
    ".": {
      "types": "./dist/index.d.ts",
      "default": "./dist/index.js"
    }
  }
}

Whereas this project points to source files and will not have a build task.

packages/pkg1/package.json

{
  "name": "@acme/pkg1",
  "exports": {
    "./package.json": "./package.json",
    ".": "./src/index.ts"
  }
}

View Inferred Tasks

To view inferred tasks for a project, open the project details view in Nx Console or run nx show project my-project in the command line.

@nx/js Configuration

The @nx/js/typescript plugin is configured in the plugins array in nx.json.

nx.json

{
  "plugins": [
    {
      "plugin": "@nx/js/typescript",
      "options": {
        "typecheck": {
          "targetName": "typecheck"
        },
        "build": {
          "targetName": "build",
          "configName": "tsconfig.lib.json"
        }
      }
    }
  ]
}

You can also set typecheck and build options to false to not infer the corresponding tasks.

nx.json

{
  "plugins": [
    {
      "plugin": "@nx/js/typescript",
      "options": {
        "build": false
      }
    }
  ]
}

Disable Typechecking

To disable typecheck task for a specific project, set the nx.addTypecheckTarget property to false in tsconfig.json.

packages/pkg1/tsconfig.json

{
  "extends": "../../tsconfig.base.json",
  "files": [],
  "include": [],
  "references": [
    {
      "path": "./tsconfig.lib.json"
    }
  ],
  "nx": {
    "addTypecheckTarget": false
  }
}

Create Libraries

You can add a new JS/TS library with the following command:

nx g @nx/js:lib libs/my-lib

Build

You can build libraries that are generated with a bundler specified.

nx g @nx/js:lib libs/my-buildable-lib --bundler=rollup

Generating a library with --bundler specified will add a build target to the library's project.json file allows the library to be built.

nx build my-buildable-lib

Test

You can test a library with the following command:

nx test my-lib

Lint

You can lint a library with the following command:

nx lint my-lib

Compiler

By default, @nx/js uses TypeScript Compiler (TSC), via @nx/js:tsc executor, to compile your libraries. Optionally, you can switch tsc out for a different compiler with --compiler flag when executing the generators.

Currently, @nx/js supports the following compilers:

• Speedy Web Compiler (SWC)

SWC

• Create a buildable library with swc

nx g @nx/js:lib libs/my-swc-lib --bundler=swc

• Convert a tsc library to use swc

nx g @nx/js:convert-to-swc my-buildable-lib

Now the build command will use @nx/js:swc executor to compile your libraries.

The first time you generate a swc library or convert a tsc library over to swc, @nx/js will install the necessary dependencies to use swc.