Custom functions in rules in Firebase - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a custom function named isOwner.

Firebase

function [1](userId) {
  return request.auth.uid == userId;
}

Drag options to blanks, or click blank then click option'

AcheckUser

BisOwner

CvalidateUser

DownerCheck

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name that does not match the rule call.

Misspelling the function name.

The function name must be isOwner to match the rule usage.

2fill in blank

medium

Complete the code to call the custom function isOwner inside the rule.

Firebase

allow read: if [1](resource.data.ownerId);

Drag options to blanks, or click blank then click option'

AisOwner

BcheckUser

CvalidateUser

DownerCheck

Attempts:

3 left

💡 Hint

Common Mistakes

Calling a function name that was not defined.

Forgetting to pass the ownerId parameter.

The rule calls the custom function isOwner to check ownership.

3fill in blank

hard

Fix the error in the custom function to correctly check if the user is authenticated.

Firebase

function isOwner(userId) {
  return [1] != null && request.auth.uid == userId;
}

Drag options to blanks, or click blank then click option'

Arequest.auth.uid

Brequest.auth.token

Crequest.auth

Drequest.auth.id

Attempts:

3 left

💡 Hint

Common Mistakes

Checking only request.auth.uid without verifying auth exists.

Using incorrect property names like request.auth.id.

Checking request.auth != null ensures the user is signed in before comparing user IDs.

4fill in blank

hard

Fill both blanks to define a custom function that checks if the user is an admin or the owner.

Firebase

function [1](userId) {
  return request.auth != null && (request.auth.token.admin == true || request.auth.uid == [2]);
}

Drag options to blanks, or click blank then click option'

AisAdminOrOwner

BuserId

CownerId

DisOwner

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect function names that do not describe the check.

Using wrong variable names inside the function.

The function isAdminOrOwner checks if the user is an admin or matches the userId parameter.

5fill in blank

hard

Fill the blanks to write a rule that allows write if the user is admin or owner using the custom function.

Firebase

allow write: if [1](resource.data.[2]);

Drag options to blanks, or click blank then click option'

AisAdminOrOwner

BownerId

Cadmin

DisOwner

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong function name in the rule.

Using incorrect data field names.

The rule calls isAdminOrOwner(resource.data.ownerId).