CODEWITHSUNDEEP
firebasegoogle-cloud-platformgoogle-cloud-firestorefirebase-security
umang kaul
umang kaul

Reputation: 43

Find the last element present in the array via Firestore rules

I am trying to work on restricting people who are able to like the posts on an application built on firebase.

I need to verify if the last element of the array exists. However, I am unable to find the last element present inside array.

I have an array 'Likes' in cloud firestore which has 2 parts - userName and userId

How will I be able to find the last userId present in the array via firestore rules

I have tried below as can be done in python but doesnt work -

request.resource.data.likes[-1].userId

Upvotes: 1

Views: 356

Answers (1)

Frank van Puffelen
Frank van Puffelen

Reputation: 598765

What you call an array, is actually known as a List object in Firestore security rules. This type indeed does not recognize negative offsets (honestly: most systems I know of don't), but you can get the same by using size.

So something like:

request.resource.data.likes[request.resource.data.likes.size()-1].userId

Upvotes: 2

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