Handle CORS OPTIONS in Nginx

site-name.conf

# inside location block
if ($request_method = OPTIONS ) {
    add_header Access-Control-Allow-Origin "$http_origin";
    add_header Access-Control-Allow-Methods "GET, OPTIONS";
    add_header Access-Control-Allow-Headers "Authorization";
    add_header Access-Control-Allow-Credentials "true";
    add_header Content-Length 0;
    add_header Content-Type text/plain;
    return 200;
}