My Angular app runs fine locally but I haven't figured out how to do the same with a Docker image. Outside of Docker, the UI runs on port 4200 with ng serve and the API serves data from 8080 with node server.js.
My Dockerfile is set up so it can get the Node server running and available on 8080, but the Angular UI won't run. I've tried several options but right now I have:
FROM node:14.17.3
COPY package*.json ./
EXPOSE 4200 8080
RUN npm install -g @angular/cli
RUN npm install --only=production
COPY . ./
RUN ng serve
CMD ["node", "server.js"]
It fails on ng serve with the error: The serve command requires to be run in an Angular project, but a project definition could not be found. I do have an angular.json file in the root. I'm not sure what I am missing. I read that ng serve shouldn't be used in this situation but the alternatives I've seen haven't made a difference.
EDIT 8/10/21: Based on the answers here and a bunch of research, this will display the UI with nginx:
FROM node:12.16.1-alpine as build
WORKDIR /usr/src/app
COPY package*.json ./
RUN npm ci --only=production
COPY . .
# RUN npm install -g @angular/cli
# RUN npm run build --prod
FROM nginx:1.15.8-alpine
COPY --from=build /usr/src/app/dist /usr/share/nginx/html
# CMD ["node", "server.js"]
However, the npm run build step fails because ng is not found despite installing @angular/cli. I have to run this manually to build the dist folder. And I can't run node server.js alongside this. It seems I can only get the front end or back end, not both.

ng serveis only for developmentnodeto serve thejsfiles in/distonce Angular has run a build. Like @robert says,ng serveis a development command.distfolder. You need to copy the content of that folder under your webserver.