Why i still getting an undefined return here?-CodePudding

Im trying to get the Value from my Firestore DB Async Function cvUpload. But no matter how long i wait for the value it is still undefined if i call it on my component.

I see many have the same issues with async await and promises . But i really not able to solve it. I really need some hints here.

DatabaseService.ts

export class DatabaseService {

constructor(
   private dbService : DatabaseService ) {}


async cvUpload (id : string) {
   const userRef = collection(this.db, this.user_db)
   const q = query(userRef, where("id", "==", id));
   const querySnapshot = await getDocs(q);

   querySnapshot.forEach((doc) => {
     console.log(doc.data().cv) /// False (Thats correct)
     return   doc.data().cv;
});
}

DashboardComponent.ts

  constructor(
    private dbService : DatabaseService ) {
   }

   async ngOnInit() {
    await this.checkCV('uyDer0BxoVekGU2XnYa3Xm77nm03')
   }


    async checkCV(id : any)  {
     let result = await this.dbService.cvUpload(id) /// This shoud return FALSE
     }

I am grateful for any help or tip that will take me further here

CodePudding user response：

the actual mistake lies in the cvUpload method. You're actually returning nothing from the cvUpload function. Returning something inside a Array.forEach() doesn't count as cvUpload's return value.

Maybe you should just return

async cvUpload(id: string) {
        const userRef = collection(this.db, this.user_db)
        const q = query(userRef, where("id", "==", id));
        const querySnapshot = await getDocs(q);
    
        return querySnapshot.docs[0].data().cv;
    };

CodePudding user response：

First of all, here:

querySnapshot.forEach((doc) => {
     console.log(doc.data().cv) /// False (Thats correct)
     return   doc.data().cv;
...

You are doing a forEach...I guess that you are waiting to recive just 1 only item... But if not, be careful because you only would treat the first element...

Any way, assuming that you will only have one element in there:

Probably you are having problem with the "falsy" returning value...Could you try to treat all of these with an object, to check if it still happens?.

Something like this:

DatabaseService.ts

querySnapshot.forEach((doc) => {
     console.log(doc.data().cv) /// False (Thats correct)
     const result: {result: boolean};
     result = { result: doc?.data()?.cv ?? false, };
     return result;
});

DashboardComponent.ts

async checkCV(id : any)  {
     const {result} = await this.dbService.cvUpload(id) /// This shoud return FALSE
}