fake-server.js

function fakeFetchData(url, args) {
  return new Promise((resolve, reject) => {
    setTimeout(function() {
      // here in the resolve, you can pass any object that you want
      // to simulate the server response
      return resolve({
        posts: [
          {
            id: 1,
            title: 'Somthing goes here',
            contents: 'Lorem ipsum'
          },
          {
            id: 2,
            title: 'Some other contents',
            contents: 'More lorem ipsum'
          }
        ]
      });
    }, 500); // wait 0.5s
  });
}

// This call simulates a server call, waits 0.5s and returns
// a successful payload
fakeFetchData('/posts').then(responseData => {
  console.log(responseData);
});