This worked for me:
location / {
alias /path/to/my/indexfile/;
try_files $uri /index.html;
}
This allowed me to create a catch-all URL for a javascript single-page app. All static files like css, fonts, and javascript built by npm run build will be found if they are in the same directory as index.html.
If the static files were in another directory, for some reason, you'd also need something like:
# Static pages generated by "npm run build"
location ~ ^/css/|^/fonts/|^/semantic/|^/static/ {
alias /path/to/my/staticfiles/;
}