Using fetch() to get data from API

Question

I'm using fetch() for the first time to get some data from the API: 'https://www.codewars.com/api/v1/users/thenarfer'.

My goal is to console.log the data. I believe the data to be in JSON format.

The error I get with the following code is:

Uncaught ReferenceError: data is not defined

Is POST or GET the correct approach? How do I continue from here?

fetch('https://www.codewars.com/api/v1/users/thenarfer', {
    method: 'GET',
    mode: 'no-cors',
    credentials: 'include',
    body: JSON.stringify(data),
    headers: {
      'Content-Type': 'application/json'
    }
  }).then((res) => res.json())
  .then((data) => {
    console.log(data)
  })
  .catch((err) => console.log(err));