使用 FieldValue.arrayUnion() 未处理的拒绝

Question

I'm working on making a social media clone and when I'm trying to follow another profile I'm getting thrown an error. When I try to console.log("follow user") it'll work just fine but when I change it to onClick={handleFollowUser} it'll throw an error saying that something is undefined.

You can view the specific error here: https://imgur.com/Lit4iqv

The error I get is:

Unhandled Rejection (FirebaseError): Function FieldValue.arrayUnion() called with invalid data. Unsupported field value: undefined (found in document users/pX1fay49L6fLiYwnzIXL)

  async function handleFollowUser() {
    setFollowed(true);
    await updateLoggedInUserFollowing(loggedInUserDocId, profileId, false);
    await updateFollowedUserFollowers(profileDocId, userId, false);
  }

      <button
        className="text-xs font-bold text-blue-medium"
        type="button"
        onClick={handleFollowUser}
        // onClick={console.log('Follow this user!')}
      >
        Follow
      </button>

  export async function updateLoggedInUserFollowing(
    loggedInUserDocId, // currently logged in user document id (gore's profile)
    profileId, // the user that gore requests to follow
    isFollowingProfile // true/false (am i currently following this person?)
  ) {
    return firebase
      .firestore()
      .collection('users')
      .doc(loggedInUserDocId)
      .update({
        following: isFollowingProfile ? FieldValue.arrayRemove(profileId) : FieldValue.arrayUnion(profileId)
      });
  }
  
  export async function updateFollowedUserFollowers(
    profileDocId, // currently logged in user document id (gore's profile)
    loggedInUserDocId, // the user that gore requests to follow
    isFollowingProfile // true/false (am i currently following this person?)
  ) {
    return firebase
      .firestore()
      .collection('users')
      .doc(profileDocId)
      .update({
        followers: isFollowingProfile
          ? FieldValue.arrayRemove(loggedInUserDocId)
          : FieldValue.arrayUnion(loggedInUserDocId)
      });
  }

Answer 1

As @Frank van Puffelend said, you're trying to write an undefined value to your database and this will trow an error. You can fix in several ways, one is to make Firebase ignore the undefined values. An example is:

import * as firestore from "firebase-admin"

const db = firestore.firestore();
db.settings({ ignoreUndefinedProperties: true })