Why isn't my http.createServer working in NodeJS?

Question

I need help with my NodeJS code. The program is working but my server is not being created. Any ideas why? The problem is, I suspect my fs.readFile and fs.writeFile are generating errors, but that doesn't make sense because it would log them. Also, is there something wrong with my http.createServer syntax, like a problem with the res.writeHead?

My code is here:

let http = require("http");
let fs = require('fs');
let readline = require("readline");
let rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});

rl.question("Do you have an html file here? y/n ", function(bool) {
  if (bool == "y") {
    rl.question("What is its name? ", function(file) {
      fs.readFile(file, (err, data) => {
        if (err) console.log(err);
        rl.question("What code to add? ", function(additionalData) {
          
          http.createServer((req, res) => {
            res.writeHead(200, {'Content-Type': 'text/html'});
            res.write(data + additionalData);
            res.end();
          })
          fs.writeFile(file, data + additionalData, err => {
            if (err) console.log(err);
          })
        })
      })
    })
  }
  else {
    rl.question("New file name: ", function(name) {
      rl.question("Data: ", function(data) {
        fs.writeFile(name, data, err => {
          if (err) console.log(err);
        })
        fs.readFile(name, (err, data) => {
          if (err) console.log(err);
          http.createServer(function(req, res) {
            res.writeHead(200, {'Content-Type': 'text/html'});
            res.write(data);
            res.end();
          })
        })
      })
    })
  }
})