Dockerfile for building a separate container for a React frontend in `priv/admin` directory of an Elixir application

default.conf

server {
  listen       80;
  server_name  localhost;

  location / {
      gzip_static on;
      root   /usr/share/nginx/html;
      try_files $uri /index.html;
  }

  location = /50x.html {
      root   /usr/share/nginx/html;
  }
}

Dockerfile.frontend

# Build step
FROM node:12.8 as build
WORKDIR /app
COPY ./priv/admin .
RUN npm install
RUN npm run-script build --frozen-lockfile --non-interactive

# Release step
FROM nginx:1.17.2-alpine
COPY ./priv/admin/nginx/default.conf /etc/nginx/conf.d/default.conf
COPY --from=build /app/build /usr/share/nginx/html