Document how to add npm (or yarn)

.dockerignore

@@ -19,6 +19,7 @@
 **/Thumbs.db
 .github/
 docs/
+node_modules/
 public/bundles/
 tests/
 var/

README.md

@@ -31,10 +31,11 @@ A [Docker](https://www.docker.com/)-based installer and runtime for the [Symfony
 1. [Build options](docs/build.md)
 2. [Using Symfony Docker with an existing project](docs/existing-project.md)
 3. [Support for extra services](docs/extra-services.md)
-4. [Deploying in production](docs/production.md)
-5. [Debugging with Xdebug](docs/xdebug.md)
-6. [Using a Makefile](docs/makefile.md)
-7. [Troubleshooting](docs/troubleshooting.md)
+4. [Building CSS and JS](docs/build-css-js.md)
+5. [Deploying in production](docs/production.md)
+6. [Debugging with Xdebug](docs/xdebug.md)
+7. [Using a Makefile](docs/makefile.md)
+8. [Troubleshooting](docs/troubleshooting.md)
 
 ## Credits
 

docs/build-css-js.md

@@ -0,0 +1,71 @@
+# Building CSS and JS
+
+For security reason and limit the size of the container, the default stack doesn't include any development "artifacts".
+To add it to the project and your development workflow follow this guide.
+
+*This example uses `npm` and [Webpack Encore](https://symfony.com/doc/current/frontend.html).*
+
+Modify `Dockerfile` to build your assets :
+
+- At the top of the file before anything else
+```diff
+ARG PHP_VERSION=8.1
+ARG CADDY_VERSION=2
++ARG NODE_VERSION=18
++
++# node "stage"
++FROM node:${NODE_VERSION}-alpine AS symfony_node
++
++WORKDIR /srv/app
++
++COPY package*.json ./
++
++RUN npm install
++## If you are building your code for production
++# RUN npm ci --only=production
++
++## You need to copy everything to use PostCSS, Tailwinds, ... 
++COPY . .
++
++RUN npm run build
+
+# "php" stage
+```
+
+- Then copy the built output in `public/build` (the configuration default) to the `php` container (which will then be copied later to `caddy`).
+
+```diff
+VOLUME /srv/app/var
+
++COPY --from=symfony_node /srv/app/public/build public/build
+
+ENTRYPOINT ["docker-entrypoint"]
+CMD ["php-fpm"]
+
+FROM caddy:${CADDY_VERSION}-builder-alpine AS symfony_caddy_builder
+```
+
+Modify `docker-compose.override.yml` to add a `node` container in your development environment.
+This will provide you with hot module reloading.
+
+```diff
+  caddy:
+    volumes:
+      - ./docker/caddy/Caddyfile:/etc/caddy/Caddyfile:ro
+      - ./public:/srv/app/public:ro
+
++  node:
++    build:
++      context: .
++      target: symfony_node
++    volumes:
++      - ./:/srv/app
++    ports:
++     - target: 8080
++       published: 8080
++       protocol: tcp
++    command: 'sh -c "npm install; npm run dev-server -- --server-type https --client-web-socket-url https://localhost:8080 --host 0.0.0.0"'
+```
+
+If file changes are not picked up, refer to this page:
+https://symfony.com/doc/current/frontend/encore/virtual-machine.html#file-watching-issues