Dockerizing Angular5 app for both development and production environment

Question

I am absolute beginner to docker. trying to dockerize my app. running in couple of issues. I have setup my Dockerfile so angular app build for using ng build. But of course the container exit after transpiling. well, I need it to listen for the code changes and transpile again. I thought ng serve would help me to achieve the desired functionality. Unfortunately, it hangs in ng serve step while trying to build the image using docker-compose build.

Angular Dockerfile

FROM node:9
ADD package.json /tmp/package.json
RUN cd /tmp && npm install
RUN mkdir -p /app && cp -a /tmp/node_modules /app
WORKDIR /app
ADD . /app

# build application
RUN npm run build

nginx DockerFile

FROM tutum/nginx
RUN rm /etc/nginx/sites-enabled/default
ADD sites-enabled/ /etc/nginx/sites-enabled

nginx configuratioins

server {

  listen 80;

  sendfile on;

  default_type application/octet-stream;

  gzip on;
  gzip_http_version 1.1;
  gzip_disable      "MSIE [1-6]\.";
  gzip_min_length   256;
  gzip_vary         on;
  gzip_proxied      expired no-cache no-store private auth;
  gzip_types        text/plain text/css application/json application/javascript application/x-javascript text/xml application/xml application/xml+rss text/javascript;
  gzip_comp_level   9;


  root /app/dist;


  location / {
    try_files $uri $uri/ /index.html =404;
  }

docker-compose.yml

version: "3.3"
services:

  nginx:
    build:
      context: ./nginx
    ports:
      - 8080:80
    volumes:
      - app:/app
      - ./:/app
  client:
    build:
      context: ./client
    volumes:
      - app:/app

volumes:
  app:

when I hit localhost:8080. I can see the first page.

any help is fully appreciated. thanks