nx/docs/shared/packages/js/js-plugin.md

---
title: Overview of the Nx JS Plugin
description: The Nx JS plugin contains executors and generators that are useful for JavaScript/TypeScript projects in an Nx workspace.
---

# @nx/js

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

## Setting Up @nx/js

### Installation

{% callout type="note" title="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](/recipes/tips-n-tricks/keep-nx-versions-in-sync).
{% /callout %}

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

```shell {% skipRescope=true %}
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.

{% tabs %}
{%tab label="npm"%}

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

{% /tab %}
{%tab label="yarn"%}

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

{% /tab %}
{% /tabs %}

{% callout type="note" title="Modernized monorepo setup" %}
Nx 20 updates the TS monorepo setup when using `--preset=ts`. The workspace is set up with [TypeScript Project References](https://www.typescriptlang.org/docs/handbook/project-references.html) along with the Workspaces feature from [npm](https://docs.npmjs.com/cli/using-npm/workspaces), [yarn](https://yarnpkg.com/features/workspaces), [pnpm](https://pnpm.io/workspaces), and [bun](https://bun.sh/docs/install/workspaces).

To create with the older setup for TS monorepo with `compilerOptions.paths`, use `create-nx-workspace --preset=apps`.
{% /callout %}

### 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.

```json {% fileName="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.

```json {% fileName="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](/concepts/inferred-tasks) 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`.

```json {% fileName="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.

```json {% fileName="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`.

```json {% fileName="packages/pkg1/tsconfig.json" highlightLines=["10-12"] %}
{
  "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:

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

## Build

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

```shell
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.

```shell
nx build my-buildable-lib
```

## Test

You can test a library with the following command:

```shell
nx test my-lib
```

## Lint

You can lint a library with the following command:

```shell
nx lint my-lib
```

## Compiler

By default, `@nx/js` uses [TypeScript Compiler (TSC)](https://www.typescriptlang.org/docs/handbook/2/basic-types.html#tsc-the-typescript-compiler), 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)](https://swc.rs)

### SWC

- Create a buildable library with `swc`

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

- Convert a `tsc` library to use `swc`

```shell
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`.