async-await2.js

/**
 * This function returns a promise to fetch a user by id
 */
function getUserWithId(id) {
    return new Promise((resolve, reject) => {
        // Look for a user with id in the database
        User.find({_id: id}, (user, err) => {
            if(err) return reject(err);

            // on success
            resolve(user); // from pending --> resolved
        });
    });
}

/**
 * This function returns a promise to fetch a list of friends
 */
function getUserWithFriends(id) {
    return new Promise((resolve, reject) => {
        // Look for a user with id in the database
        Friends.find({friends.id: id}, (friends, err) => {
            if(err) return reject(err);

            // on success
            resolve(friends); // from pending --> resolved
        }
    });
}
                       
function getUserImage(url) {
    return new Promise((resolve, reject) => {
        // Look for a user with id in the database
        http.get({link: url}, (image, err) => {
            if(err) return reject(err);

            // on success pass the image
            resolve(image);
        });
    });
}
    
/**
 * No chaininig promises anymore, this looks much cleaner.
 */
async function performMultipleTasks(req, res, next) {
    try {
        // Now the method calls look like synchronous calls, which is more cleaner and easier to read
        const user = await getUserWithId(req.params.id);
        const friends = await getFriendsFromUser(user); // sorry for renaming this function
        const image = await getUserImage(user.imageUrl);
        
        return next();
    } catch(err) {
        // do something with the error
    }
}
    
performMultipleTasks(req, res, next);