Currently, I am utilizing ExpressJS for handling APIs and heavily rely on promises for managing asynchronous requests such as external API calls and database queries. While this approach works well in most cases, it tends to clutter the code with numerous .then -> .catch statements when dealing with a large number of calls. To illustrate, consider the following snippet of a login API that involves API calls and database queries:
const loginUser = (req, res) => {
const { body } = req;
console.log('Login');
if (!body) {
return res
.status(400)
.json({ success: false, error: 'request body is empty' });
}
if (!body.authCode) {
return res
.status(400)
.json({ success: false, error: 'authCode missing in the body' });
}
getLinkedInProfile(body.authCode)
.then((linkedInProfile) => {
User.findOne({ linkedInId: linkedInProfile.linkedInId })
.then((user) => {
if (user) {
Token.findOne({ userId: user._id })
.then((token) => {
// Handle token logic here
})
.catch((err) => {
// Error handling for finding token
});
} else {
// User does not exist response
}
})
.catch((err) => {
// Database query error response
});
})
.catch((err) => {
// LinkedIn profile authentication error response
});
};
If you have any suggestions or improvements to streamline this code, please feel free to share your insights!