Dockerfile and nginx.conf that supports Angular's path-based routing

Dockerfile

FROM node:14.1-alpine AS builder

WORKDIR /opt/web
COPY package.json package-lock.json ./
RUN npm install

ENV PATH="./node_modules/.bin:$PATH"

COPY . ./
RUN ng build --prod

FROM nginx:1.17-alpine
RUN apk --no-cache add curl
RUN curl -L https://github.com/a8m/envsubst/releases/download/v1.1.0/envsubst-`uname -s`-`uname -m` -o envsubst && \
    chmod +x envsubst && \
    mv envsubst /usr/local/bin
COPY ./nginx.config /etc/nginx/nginx.template
CMD ["/bin/sh", "-c", "envsubst < /etc/nginx/nginx.template > /etc/nginx/conf.d/default.conf && nginx -g 'daemon off;'"]
COPY --from=builder /opt/web/dist/notes /usr/share/nginx/html

nginx.config

server {
    listen       ${PORT:-80};
    server_name  _;

    root /usr/share/nginx/html;
    index index.html;

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

Commands that work:

docker run -p 4200:80 ng-notes
docker run -e PORT=1234 -p 4200:1234 ng-notes
heroku container:push web --remote docker
heroku container:release web --remote docker