How to get response from http server?

Question

Node.js

var fetch = require('node-fetch');
function getcode(data) {
fetch("http://127.0.0.1:9000/?"+data, {
    method: 'GET',
    body: null,
    headers: { 'Content-Type': 'application/json' }
})
  .then(res => res.json())
  .then(return json)//как сделать чтобы ретурн работал?
}
var code = getcode("данные_на_сервер")
console.log(code)

what can be corrected in the code, replaced?