nginx.conf

# Source: https://dev.to/oneofthedevs/docker-angular-nginx-37e4

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 /usr/share/nginx/html;
  
  location / {
    # The most important part:
    try_files $uri $uri/ /index.html =404;
    # That tells Nginx to try to match the files it is requested in the URL (URI) with files it has available. That will make it, for example, match the /main.bundle.js and return the JavaScript file. But when there's no match, it will default to index.html.
    # That will make it return the index.html for any other URL it receives, so, all the Angular router URLs will work, even when going to the URL directly in the browser (not being redirected from an internal section of the app).
    # Without that, if you had a route like /app/dashbaord/main, when you tried to open that URL, Nginx wouldn't find the file app/dashboard/main and would return a 404 Not found, instead of returning the index.html and letting the Angular router handle it.
    # The last part, =404 tells Nginx to return a 404 if it doesn't even find an index.html file. That's the default case. But you will normally always have an index.html file.
  }
}