Nest.js Plugin for Nx

Nest.js is a framework designed for building scalable server-side applications. In many ways, Nest is familiar to Angular developers:

• It has excellent TypeScript support.
• Its dependency injection system is similar to the one in Angular.
• It emphasises testability.
• Its configuration APIs are similar to Angular as well.

Many conventions and best practices used in Angular applications can be also be used in Nest.

Setting Up @nx/nest

Generating a new workspace

To create a new workspace with Nest, run the following command:

npx create-nx-workspace my-workspace --preset=nest

Yarn users can use the following command instead:

yarn create nx-workspace my-workspace --preset=nest

Installation

Keep Nx Package Versions In Sync

Make sure to install the @nx/nest 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/nest by running the following command:

nx add @nx/nest

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

Create Applications

You can add a new Nest application with the following command:

nx g @nx/nest:app apps/my-nest-app

Application Proxies

Generating Nest applications has an option to configure other projects in the workspace to proxy API requests. This can be done by passing the --frontendProject with the project name you wish to enable proxy support for.

nx g @nx/nest:app apps/my-nest-app --frontendProject my-angular-app

Create Libraries

You can add a new Nest library with the following command:

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

To make the library buildable, use the following command:

nx g @nx/nest:lib libs/my-nest-lib --buildable

To make the library publishable, use the following command:

nx g @nx/nest:lib libs/my-nest-lib --publishable --importPath=@my-workspace/my-nest-lib

Read more about building and publishing libraries here.

Nest Generators

The Nest plugin for Nx extends the generators provided by Nest. Any commands that can be used with the Nest CLI can also be used with the nx command. The --project flag should be used for all Nest generators.

--project is used to infer the root of the project where the generators will generate the files.

Using Nest

Build

You can build an application with the following command:

nx build my-nest-app

This applies to buildable libraries as well

nx build my-nest-lib

Waiting for other builds

Setting the waitUntilTargets option with an array of projects (with the following format: "project:target") will execute those commands before serving the Nest application.

Serve

You can serve an application with the following command:

nx serve my-nest-app

The serve command runs the build target, and executes the application.

By default, the serve command will run in watch mode. This allows code to be changed, and the Nest application to be rebuilt automatically.

Debugging

Nest applications also have the inspect flag set, so you can attach your debugger to the running instance.

VSCode Integration

When generating Nest applications, Nx automatically creates a VSCode debugging configuration for seamless development experience:

• Automatic setup: A .vscode/launch.json file is created with pre-configured debugging settings.
• Smart port allocation: Debug ports are automatically assigned starting from 9229, preventing conflicts between multiple applications.
• Source map support: Webpack configurations include devtoolModuleFilenameTemplate for accurate source mapping.
• Multi-format support: Supports debugging .js, .mjs, and .cjs output files.

To debug your Nest application in VSCode:

1. Open your workspace in VSCode.
2. Set breakpoints in your TypeScript source files.
3. Go to the Debug panel (Ctrl+Shift+D).
4. Select "Debug {your-app-name} with Nx" from the dropdown.
5. Click the play button or press F5.

The debugger will automatically:

• Start your application with nx serve.
• Attach to the Node.js debugger on the allocated port.
• Map compiled JavaScript back to your TypeScript source files.

Manual Debugging

For advanced debugging scenarios, you can manually configure the debug port by setting the port option in the serve target in the project.json, or by running the serve command with --port <number>.

For additional information on Node.js debugging, see the Node.js debugging getting started guide.

Lint

You can lint an application with the following command:

nx lint my-nest-app

You can lint a library with the following command:

nx lint my-nest-lib

Unit Test

You can run unit test for an application with the following command:

nx test my-nest-app

You can run unit test for a library with the following command:

nx test my-nest-lib

Using CLI Plugins

Nest supports the use of various CLI plugins to enhance the development experience. Plugins can be configured via transformers property in NxWebpackPlugin. As an example, to set up a Swagger plugin, modify the Nest application's Webpack configuration as follows:

const { NxWebpackPlugin } = require('@nx/webpack');

module.exports = {
  // ...
  plugins: [
    new NxWebpackPlugin({
      // ...
      transformers: [
        {
          name: '@nestjs/swagger/plugin',
          options: {
            dtoFileNameSuffix: ['.dto.ts', '.entity.ts'],
          },
        },
      ],
    }),
  ],
};

Deployment

Ensuring a smooth and reliable deployment of a Nest.js application in a production environment requires careful planning and the right strategy. Depending on your specific needs and infrastructure, you can choose from several deployment approaches. Below are four commonly used methods:

1. Using Docker: Create a Dockerfile that specifies the application's environment and dependencies. Build a Docker image and optionally push it to a container registry. Deploy and run the Docker container on the server. Utilize the @nx/node:setup-docker generator to streamline the Docker setup process.

2. Installing Dependencies on the Server: Transfer the build artifacts to the server, install all dependencies using the package manager of your choice, and start the application. Ensure that NxAppWebpackPlugin is configured with generatePackageJson: true so that the build artifacts directory includes package.json and package-lock.json (or the equivalent files for other package managers).

3. Transferring Pre-installed Dependencies: Install dependencies during the build process, and transfer the build artifacts along with the node_modules directory to the server. Typically, the artifacts are archived for faster transfer and then unarchived on the server.

4. Bundling Dependencies: By default, Nx/Nest creates a setup that externalizes all dependencies, meaning they are not included in the bundle. This behavior can be adjusted using the externalDependencies parameter in the webpack configuration with NxAppWebpackPlugin. After bundling, transfer the package to the server and start the application.

Bundling Dependencies

Bundling dependencies is typically not recommended for Node applications.

More Documentation

• Using Jest