Node Multi‑Stage Dockerfile

Building Docker images for Node apps can be slow if dependencies are reinstalled on every build. Using multi‑stage builds and layering strategically reduces build times and produces smaller images. This example installs dependencies in a base layer, copies only the package files needed for npm install, builds the app, then copies the build into a slim runtime image.

# ----- build stage -----
FROM node:18-bullseye AS build
WORKDIR /app
 
# Install dependencies based on package files
COPY package*.json ./
RUN npm ci
 
# Copy source and build
COPY . .
RUN npm run build
 
# ----- runtime stage -----
FROM node:18-bullseye-slim AS runtime
WORKDIR /app
 
# Copy node_modules from build stage
COPY --from=build /app/node_modules ./node_modules
# Copy built assets
COPY --from=build /app/dist ./dist
 
# Set the runtime command
CMD ["node", "dist/index.js"]

This Dockerfile caches the npm ci layer unless your package.json or package-lock.json change. The final image contains only the compiled code and dependencies, reducing size and attack surface. Adjust the dist path and CMD line based on your build output and entry point.