我的异步 function 没有等待来自 Firebase 的 promise

Question

I am currently learning how async works, while working on a small project using Firebase databases. As far as I understand await should pause the function until a promise is resolved, but in my case it's not waiting for that.

I've shortened 2 functions I used to try and test this:

async findUser(id) {
        await this.firebase.findUserData(id).then(
            value => {
                console.log('finduser stopped waiting');
                return value;
            }
        )
    }

async findUserData(userId){
        console.log('firebase started looking for user');
        firebase.database().ref('/users/' + userId).once('value').then(function(snapshot){
            let user = (snapshot.val());
            console.log('found: ' + user);
            return user;
        });
    }

The console output looks like this: (not allowed to embed images yet)

It's running findUser first, followed by the Firebase call, but does not wait for that promise to complete before returning a value. Found user id prints last.

I'm sure I'm doing something really dumb here, but I couldn't figure it out for a while now and have nobody else to turn to.

Sorry if the question is poorly written. First time posting around here. Welcome any feedback!

Answer 1

You should not mix await and then s. Then you also don't forget to await a promise (you never await / return the Promise returned by.once):

async findUserData(userId){
    console.log('firebase started looking for user');
    const snapshot = await firebase.database().ref('/users/' + userId).once('value');
    let user = (snapshot.val());
    console.log('found: ' + user);
    return user;
}

async findUser(id) {
    const value = await this.firebase.findUserData(id);
    console.log('finduser stopped waiting');
    return value;
}