CODEWITHSUNDEEP
javascriptfirebasegoogle-cloud-functionsgoogle-cloud-firestorefirebase-admin
Kravitz
Kravitz

Reputation: 2859

How to update Array field?

Im using Firebase Firestore and want to update an array field under a userprofile with the latest chat thread's id.. Im guessing that I have to pull the entire array (if it exists) from the chat node under that user, then I need to append the new id (if it doesnt exist) and update the array.. It works when theres only 1 value in the array then it fails after that with the following error:

Transaction failed: { Error: Cannot convert an array value in an array value. at /user_code/node_modules/firebase-admin/node_modules/grpc/src/node/src/client.js:554:15 code: 3, metadata: Metadata { _internal_repr: {} } }

and here is my firebase cloud function, can anyone tell me where im going wrong ?

  exports.updateMessages = functions.firestore.document('messages/{messageId}/conversation/{msgkey}').onCreate(  (event) => {
    /// console.log('function started');
    const messagePayload = event.data.data();
    const userA = messagePayload.userA;
    const userB = messagePayload.userB;     
    // console.log("userA " + userA);
    // console.log("userB " + userB);  
    // console.log("messagePayload " + JSON.stringify(messagePayload, null, 2) );    

  const sfDocRef = admin.firestore().doc(`users/${userB}`);

  return admin.firestore().runTransaction( (transaction) => {

      return transaction.get(sfDocRef).then( (sfDoc) => {

          const array = [];
          array.push(...[event.params.messageId, sfDoc.get('chats') ]);

          transaction.update(sfDocRef, { chats: array } ); 

      });
  }).then( () => {
      console.log("Transaction successfully committed!");
  }).catch( (error) => {
      console.log("Transaction failed: ", error);
  });  

  });

Upvotes: 2

Views: 1501

Answers (2)

Ggrimaldo
Ggrimaldo

Reputation: 327

I have looked further into the matter, and I would follow the advice that Frank gave you in his post; allocate the data in collections rather than with arrays as they have greater versatility for Firebase 1. Researching under the examples listed in the Firebase website looking for anything related to a chat, I’ve found the data structure and code for messages that are used by Firechat as they might be of use for you.

In the source code, they use a collection for the their message-id -userId pair with the following topology 2 : Topology of the Example

The exact way how the saving is executed at the repository is 3 : Append sentence

It executes an append of the message into the Room-id collection. Instead of this structure, you could use an userID - messageID pair as it might fit you better.

Upvotes: 0

Frank van Puffelen
Frank van Puffelen

Reputation: 598728

You're nesting arrays in your code here:

const array = [];
array.push(...[event.params.messageId, sfDoc.get('chats') ]);

This leads to an array with two values, the first one being the new messageId and the second value contains an array all of your previous values, e.g.

[ "new message id", ["previous id", "older id"] ]

This type of nested array is something that Firestore (apparently) doesn't allow to be stored.

The solution is simple:

const array = [event.params.messageId, ...sfDoc.get('chats')];

The fact that you have to first load the array to then add a single element to it is one of reasons Firebasers recommend not storing data in arrays. Your current data looks like it'd be better off as a set, as shown in the Firestore documenation:

{
  "new message id": true, 
  "previous id": true, 
  "older id": true
}

That way adding a chat ID is as simple as:

sfDocRef.update({ "chats."+event.params.messageId, true })

Upvotes: 4

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