function normalizePort (val) {
        let port = parseInt(val, 10);

        if (isNaN(port)) {
          // named pipe
          return val;
        }

        if (port >= 0) {
          // port number
          return port;
        }

        return false;
      }
function normalizePort (val) {
        let port = parseInt(val, 10);

        if (isNaN(port)) {
          
          return val;
        }

        if (port >= 0) {
          
          return port;
        }

        return false;
      }
function normalizePort ( val ) { let port = parseInt ( val , 10 ) ; if ( isNaN ( port ) ) { // named pipe return val ; } if ( port >= 0 ) { // port number return port ; } return false ; }
Normalize a port into a number, string, or false.
Normalize a port into a number string or false .