我可以在 angular firebase 集合的数据字段内插入、更新和删除数组吗？

Question

I have a collection users and inside that collection is a filed list in which I want to add list of favourite movies of a user. User can add and remove movies as per wish. I did manage to add list as array by using push().

My function

this.userData.list.push({
  movie_id: this.movie_detail.id,
});
let data: any = {
  id: this.userData.uid,
  password: this.userData.password,
  phone: this.userData.phone,
  role: this.userData.role,
  list: this.userData.list,
};
this.authService.updateUser(data);

Update function inside service:

updateUser(user) {
    const noteDocRef = doc(this.firestore, `users/${user.id}`);
    console.log('userDAta', noteDocRef);

    return updateDoc(noteDocRef, user);
}

Right now same movie is being added multiple times. I want to prevent that. I also want to delete the movie from list if user decides to click remove button.

Answer 1

To prevent duplicates in an array field, you can either remove duplicates in your application code, or leave it to the database by using the arrayUnion operator when adding an item to the list:

const noteDocRef = doc(this.firestore, `users/${user.id}`);

updateDoc(noteDocRef, {
  list: firebase.firestore.FieldValue.arrayUnion({ movie_id: this.movie_detail.id })
}