CMD npm run dev

FROM base as prod
RUN --mount=type=bind,source=package.json,target=package.json \
    --mount=type=bind,source=package-lock.json,target=package-lock.json \
    --mount=type=cache,target=/root/.npm \
    npm ci --omit=dev
USER node
COPY . .
CMD node src/index.js
```

In the Dockerfile, you first add a label `as base` to the `FROM
node:${NODE_VERSION}-alpine` statement. This lets you refer to this build stage
in other build stages. Next, you add a new build stage labeled `dev` to install
your development dependencies and start the container using `npm run dev`.
Finally, you add a stage labeled `prod` that omits the dev dependencies and runs
your application using `node src/index.js`. To learn more about multi-stage
builds, see [Multi-stage builds](/manuals/build/building/multi-stage.md).

Next, you'll need to update your Compose file to use the new stage.

### Update your Compose file for development

To run the `dev` stage with Compose, you need to update your `compose.yaml`
file. Open your `compose.yaml` file in an IDE or text editor, and then add the
`target: dev` instruction to target the `dev` stage from your multi-stage
Dockerfile.

Also, add a new volume to the server service for the bind mount. For this application, you'll mount `./src` from your local machine to `/usr/src/app/src` in the container.

Lastly, publish port `9229` for debugging.

The following is the updated Compose file. All comments have been removed.

```yaml {hl_lines=[5,8,20,21],collapse=true,title=compose.yaml}
services:
  server:
    build:
      context: .
      target: dev
    ports:
      - 3000:3000
      - 9229:9229
    environment:
      NODE_ENV: production
      POSTGRES_HOST: db
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD_FILE: /run/secrets/db-password
      POSTGRES_DB: example
    depends_on:
      db:
        condition: service_healthy
    secrets:
      - db-password
    volumes:
      - ./src:/usr/src/app/src
  db:
    image: postgres
    restart: always