CODEWITHSUNDEEP
javascriptfirebasegoogle-cloud-firestoregoogle-cloud-functions
SNM
SNM

Reputation: 6795

Cannot read property get of undefined Firebase functions

I'm trying to create a function that will send a notification whether a document is updated.

I access the document when its updated, and I get the userId who updated that document and a status I need, after that, I just query for the user device token and send a payload, but it seems that is not working, I dont really know if there is some errors in the syntax of the code or some problems with my callbacks.

const functions = require('firebase-functions');
var admin = require("firebase-admin");

 {service keys are initialized here}     

    exports.onOrderCreated = functions.firestore
    .document('orders/{orderId}').onUpdate(async (snap,context) => {

        var db = admin.firestore();

        try{
            const orderDataSnap = await snap.ref.get();
            var userId = orderDataSnap.data().uid;
            var orderStatus = orderDataSnap.data().status;
        }catch(error){
            return handleErrorToUser(error,snap);
        }

        let docRef = db.collection('user').doc(userId);

       return docRef.get().then(userDoc => {
           const deviceToken = userDoc.get('deviceToken')
           const payload = {
            "data": {
                "title": "Your order status here !",
                "body": "Your order status is:"+orderStatus,
                "icon": "ic_launcher",
                "sound": "default",
                "click_action": "delete_token"
              }

            }
            return admin.messaging().sendToDevice(deviceToken,payload)
      });
    });

    // Inform about errors (these errors are for testing purposes, we should use StackDriver to log the errors 
    // to ourselves and let a friendly user error message with this function)
    async function handleErrorToUser(tError, snap) {
        console.log(tError)
      }

Inside orders I have to fetch this two attributes

uid and status

Then , with that uid, fetch the deviceToken inside user reference.

This code gives me 

 TypeError: Cannot read property 'get' of undefined
>     at exports.onOrderCreated.functions.firestore.document.onUpdate (/srv/index.js:17:46)
>     at cloudFunction (/srv/node_modules/firebase-functions/lib/cloud-functions.js:131:23)
>     at /worker/worker.js:825:24
>     at <anonymous>
>     at process._tickDomainCallback (internal/process/next_tick.js:229:7)

I'm not so much experienced with javascript, any help will be appreciated.

thanks

Upvotes: 1

Views: 1787

Answers (2)

Braulio David
Braulio David

Reputation: 113

I think the problem is in this line:

const deviceToken = userDoc.get('deviceToken')

If 'deviceToken' token is a property from the document data, you should first run the data method, it returns all the document data properties:

const deviceToken = userDoc.data().deviceToken

Upvotes: 2

Doug Stevenson
Doug Stevenson

Reputation: 317487

You've got a few things going wrong in here.

Firstly, the name of the first argument to your onUpdate function should probably not be snap. As you can see in the documentation for onUpdate, the first argument is a Change object that contains document snapshots for the "before" and "after" state of the document because of the update that happened. That Change object does not have a property called ref, which is causing your code to fail.

Second, if you're expecting that this code fetch the document that was updated:

const orderDataSnap = await snap.ref.get();

That is totally not necessary here, as the contents of the document are already being delivered in Change object I mentioned before. Just use the data you're being provided, unless you know for sure that it's not going to be what you want.

I suggest reviewing the documentation to get a better sense of how update triggers works.

Upvotes: 2

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