/**
 * @description ### Returns Go / Lua like responses(data, err)
 * when used with await
 *
 * - Example response [ data, undefined ]
 * - Example response [ undefined, Error ]
 *
 *
 * When used with Promise.all([req1, req2, req3])
 * - Example response [ [data1, data2, data3], undefined ]
 * - Example response [ undefined, Error ]
 *
 *
 * When used with Promise.race([req1, req2, req3])
 * - Example response [ data, undefined ]
 * - Example response [ undefined, Error ]
 *
 * @param {Promise} promise
 * @returns {Promise} [ data, undefined ]
 * @returns {Promise} [ undefined, Error ]
 */
const handle = (promise) => {
  return promise
    .then(data => ([data, undefined]))
    .catch(error => Promise.resolve([undefined, error]));
}

// Explanation
// The handle function takes a promise as an argument and always resolves it be returning an array with [data|undefined, Error|undefined].

// If the promise passed to the handle function resolves it returns [data, undefined];
// If it was rejected, the handle function still resolves it and returns [undefined, Error]

// Usage
async function userProfile() {
  let [user, userErr] = await handle(getUser());

  if(userErr) throw Error('Could not fetch user details');

  let [friendsOfUser, friendErr] = await handle(
    getFriendsOfUser(userId)
  );

  if(friendErr) throw Error('Could not fetch user\'s friends');

  let [posts, postErr] = await handle(getUsersPosts(userId));

  if(friendErr) throw Error('Could not fetch user\'s posts');

  showUserProfilePage(user, friendsOfUser, posts);
}