npm init
npm install pug
npm install fastify

import Fastify from "fastify";
 
// Fastify instance
const fastify = Fastify({logger:true});
 
 
fastify.get("/", (req, res)=>{
    res.send( "HelloWorld" )
} )
 
 
try{
    await fastify.listen({port:3000, host: "127.0.0.1"}); // Start server process, wait for it to exit
}catch(err){
    console.log(err);
    process.exit(1);
}

//package.json
//Add:
 
  "type": "module",