1// This will fetch api.example.com/comments with a header and a body
2fetch(`https://api.example.com/comments`, {
3  method: 'POST', //This could be any http method
4  headers: {
5    'Authorization': 'Basic SGVsbG8gdGhlcmUgOikgSGF2ZSBhIGdvb2QgZGF5IQ==',
6    'Content-Type': 'application/json',
7  },
8  body: JSON.stringify({
9	UID: 58,
10    Comment: "Fetch is really easy!",
11  }),
12})
13.then((response) => response.json())
14.then((newComment) => {
15  // Do something magical with your newly posted comment :)
16});

1// Fetch and Async/Await
2
3const url = 'http://dummy.restapiexample.com/api/v1/employees'; 
4const fetchUsers = async () => {
5    try {
6       const res = await fetch(url);
7     // check for 404 error
8       if (!res.ok) { 
9           throw new Error(res.status);
10       }
11       const data = await res.json();
12          console.log(data);
13       }
14       // catch block for network errors
15       catch (error) { 
16            console.log(error); 
17        }
18}
19fetchUsers( );

1// Error handling while fetching API
2
3const url = "http://dummy.restapiexample.com/api/v1/employee/40";
4fetch(url) //404 error
5     .then( res => {
6          if (res.ok) {
7                return res.json( );
8          } else {
9                return Promise.reject(res.status); 
10           }
11      })
12      .then(res => console.log(res))
13      .catch(err => console.log('Error with message: ${err}') ); 

1// Making get requests
2
3const url = "http://dummy.restapiexample.com/api/v1/employees"; 
4fetchurl()
5     .then(res => {
6            console.log(res);
7})
8      .catch(err => {
9             console.log('Error: ${err}' ); 
10});

1fetch('http://example.com/movies.json')
2  .then(response => response.json())
3  .then(data => console.log(data));
4

1// Making post request
2
3const url = 'http://dummy.restapiexample.com/api/v1/create'
4const user = {
5      name: 'Rahul'
6      age: '16'
7      salary: '000'
8};
9
10const options = {
11   method: 'POST'
12   body: JSON.stringify(user), 
13}
14
15fetch(url, options)
16     .then( res => res.json())
17     .then( res=> console.log(res));