Express Plugin

The Express plugin contains generators to add a new Express application to an Nx workspace.

Adding the Express plugin

Adding the Express plugin to a workspace can be done with the following:

#yarn
yarn add -D @nrwl/express

#npm
npm install -D @nrwl/express

Note: You can create new workspace that has Express and React set up by doing npx create-nx-workspace@latest --preset=react-express

Applications

Generating new applications can be done with the following:

nx generate @nrwl/express:application <express-app>

This creates the following app structure:

my-org/
├── apps/
    └── express-app/
        ├── jest.config.js
        ├── src/
        │   ├── app/
        │   ├── assets/
        │   ├── environments/
        │   │   ├── environment.prod.ts
        │   │   └── environment.ts
        │   └── main.ts
        ├── tsconfig.app.json
        ├── tsconfig.json
        ├── tsconfig.spec.json
        └── tslint.json

The main.ts content should look similar to this:

1import * as express from 'express';
2
3const app = express();
4
5app.get('/api', (req, res) => {
6  res.send({ message: 'Welcome to express-app!' });
7});
8
9const port = process.env.port || 3333;
10const server = app.listen(port, () => {
11  console.log(`Listening at http://localhost:${port}/api`);
12});
13server.on('error', console.error);

Application Proxies

Generating Express 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 generate @nrwl/express:application <express-app> --frontendProject my-react-app

Application commands

When a Express application is added to the workspace.json (or angular.json), the following architect commands are available for execution:

build

nx build <express-app>

The build command will compile the application using Webpack. It supports a production configuration by building with the following command:

nx build <express-app> --configuration=production

Additional configurations can be added in the workspace.json. Changing the --configuration flag with the new configuration name will run that config.

serve

nx serve <express-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 Express application to be rebuilt automatically. Express applications also have the inspect flag set, so you can attach your debugger to the running instance.

Debugging

Debugging is set to use a random port that is available on the system. The port can be changed by setting the port option in the serve architect in the workspace.json. Or by running the serve command with --port <number>.

For additional information on how to debug Node applications, see the Node.js debugging getting started guide.

Waiting for other builds

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

lint

The lint command will run linting within the scope of the Express app.

nx lint <express-app>

test

Test will execute Jest tests within the scope of the Express app.

nx test <express-app>