Angular Firestore 加入集合不起作用

Question

I have two collections that I am trying to join. Review Comments and Users.

Here is the code in my service:

 getAll(reviewID) {
    const allComments = this.af.collection<Review>(`reviews/${reviewID}/comments`, ref => ref.orderBy('dateCreated', 'desc'))
      .valueChanges()
      .pipe(
        switchMap(reviews => {
          const res = reviews.map((review: review) => {
            return this.af.collection<User>('users', ref => ref.where('userID', '==', review.userID))
            .valueChanges()
            .pipe(
              map(user => Object.assign(review, { user }))
            );
          });
          return combineLatest(...res);
        })
      );
      return allComments;
  }

Here is my component:

this.commentService.getAll(reviewID).subscribe(results => {
        this.comments = results;
        this.logger.log(this.comments);
      });

This is mostly working but it seems to return the user array every other comment.

For example:

0:
comment: "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse id quam ut lacus tempor aliquam. Curabitur efficitur, lorem sit amet sodales finibus, erat arcu imperdiet dolor, eget ultricies arcu felis sit amet enim. Interdum et malesuada fames ac ante ipsum primis in faucibus."
dateCreated: Timestamp {seconds: 1549654515, nanoseconds: 0}
userID: "c8Y3q9Mn0sdfGFDgMWqh4GqJC5B2"
user: Array(0)
1:
comment: "this is the third comment"
dateCreated: Timestamp {seconds: 1549638673, nanoseconds: 0}
userID: "KEPBML9xlDfgedGZAslzOfOfbSwh2"
user: Array(1)
0: {avatar: "img.jpg", fullname: "Michael Jones", userID: "KEPBML9xlDfgedGZAslzOfOfbSwh2", username: "michaelj"}
2:
comment: "this is the second comment"
dateCreated: Timestamp {seconds: 1549562400, nanoseconds: 0}
userID: "NbPyKuTIB5dfGDGdVNmEB1h5YG2"
user: Array(0)
3:
comment: "this is the first comment"
dateCreated: Timestamp {seconds: 1549558800, nanoseconds: 0}
userID: "N2FhiRSJcdfGEDRgrCvPZa98bU4Im2"
user: Array(1)
0: {avatar: "img.jp", fullname: "Emily Jones", userID: "N2FhiRSJcdfGEDRgrCvPZa98bU4Im2", username: "emilyj"}

I have confirmed that all userIDs are being passed.

Am I doing something wrong? I'm not sure what I'm missing, any help would be appreciated.

Answer 1

I finally figured it out. Not sure what I didn't think of this before.

To fix this I changed:

this.af.collection<User>('users', ref => ref.where('userID', '==', review.userID))

to

this.af.doc<User>( users/${review.userID} )