how to parse data from fetch request javascript code example

Example 1: js fetch 'post' json

//Obj of data to send in future like a dummyDb
const data = { username: 'example' };

//POST request with body equal on data in JSON format
fetch('https://example.com/profile', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
  },
  body: JSON.stringify(data),
})
.then((response) => response.json())
//Then with the data from the response in JSON...
.then((data) => {
  console.log('Success:', data);
})
//Then with the error genereted...
.catch((error) => {
  console.error('Error:', error);
});

//																		Yeah

Example 2: Add no cores to fetch

// There were no quick access to mode and credentials to other fetch answers.
// Data you'll be sending
const data = { funny: "Absolutely not", educational: "yas" }

fetch('https://example.com/api/', {
  method: 'POST', // The method
  mode: 'no-cors', // It can be no-cors, cors, same-origin
  credentials: 'same-origin', // It can be include, same-origin, omit
  headers: {
    'Content-Type': 'application/json', // Your headers
  },
  body: JSON.stringify(data),
}).then(returnedData => {
  // Do whatever with returnedData
}).catch(err => {
  // In case it errors.
})

Example 3: .fetch method

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