what does fetch( ) do in js code example

Example 1: http request javascript fetch

fetch('http://example.com/movies.json')
  .then(response => response.json())
  .then(data => console.log(data));

Example 2: fetch api javascript

// This will fetch api.example.com/comments with a header and a body
fetch(`https://api.example.com/comments`, {
  method: 'POST', //This could be any http method
  headers: {
    'Authorization': 'Basic SGVsbG8gdGhlcmUgOikgSGF2ZSBhIGdvb2QgZGF5IQ==',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
	UID: 58,
    Comment: "Fetch is really easy!",
  }),
})
.then((response) => response.json)
.then((newComment) => {
  // Do something magical with your newly posted comment :)
});