Pfthb

I'm trying to create a class with async method chaining. However, I'm still setting the new values before I fully fetch the data from the database. Am I missing something?

I also don't want to use any third-party modules.

/* Class */

class UserDB 
 constructor() 
 this.user = 
 this.user.username = null
 

 set(name, value) 
 this.user[name] = value
 return this
 

 update() 
 return new Promise((resolve, reject) => 
 const db = MongoConnection.client.db('database').collection('users')
 db.updateOne( _id: this.user._id , $set: this.user, (err, result) => 
 if (err) reject(err)
 resolve(this)
 )
 )
 

 findByEmail(email) 
 return new Promise((resolve, reject) => 
 const db = MongoConnection.client.db('database').collection('users')
 db.findOne( email: email , (err, result) => 
 if (err) reject(err)
 this.user = result
 resolve(this)
 )
 )
 


module.exports = UserDB


/*execution*/

new UserDB().findByEmail('email@email.com')
 .set('username', 'new_name')
 .update()

Thats indeed interesting. You could overload the returned Promise with methods that attach the operation to a .then chain:

 class AsyncChainable {
 constructor() 
 this._methods = ;

 const that = this;
 for(const key of Object.getOwnPropertyNames(Object.getPrototypeOf(this))) 
 this._methods[key] = function(...args) 
 return that.chain(this.then(() => that[key](...args)));
 
 

 chain(promise) return Object.assign(promise, this._methods); 

Then use that in your custon class:

 class User extends AsyncChainable 
 login() 
 return this.chain((async () => 
 // some logic
 )());
 

That way you can do:

 (new User).login().login().then(console.log);