To use HTTP/2 in a NodeJS application, you will need to use an HTTP/2-enabled web server, such as Nginx or Apache, as a reverse proxy for your NodeJS application. This allows the webserver to handle the HTTP/2 protocol and pass incoming requests to your NodeJS application.

To configure Nginx as a reverse proxy for a NodeJS application, you can use the proxy_pass directive in your Nginx configuration file. For example:

server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;

    ssl_certificate /path/to/ssl/certificate.crt;
    ssl_certificate_key /path/to/ssl/private.key;
    location / {
        proxy_pass http://localhost:3000;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
    }
}

In this configuration, the proxy_pass directive is used to specify the URL of the NodeJS application (running on port 3000 in this example). The other directives are used to enable HTTP/2 support and configure the reverse proxy settings. Once you have Nginx configured as a reverse proxy, your NodeJS application will be able to serve HTTP/2 requests.

To use the full range of HTTP/2 features in a Node.js application, it is recommended to use a native HTTP/2 server. A native HTTP/2 server is a server that is specifically designed to support the HTTP/2 protocol, and is built into the Node.js runtime. This allows the server to provide full support for the HTTP/2 protocol, including its advanced features such as multiplexing and server push.

In contrast, using HTTP/2 at the web server level, such as with a reverse proxy or load balancer, does not provide full support for the HTTP/2 protocol. In this case, the web server acts as a layer between the client and the application, and may not be able to support all of the features of HTTP/2. This can limit the performance benefits and capabilities of your application.

Therefore, if you want to use the full range of HTTP/2 features in your Node.js application, it is recommended to use a native HTTP/2 server. This will allow you to take advantage of the advanced capabilities of the protocol and potentially improve the performance of your application.