Identify Issue

Spot the error or unexpected behavior in your code.

TypeError: cannot read property 'foo' of undefined

Reproduce Bug

Isolate and reproduce the error reliably in your environment.

npm test --grep "User login"

Analyze Stack Trace

Trace the error back to its source in the codebase.

at loginHandler (auth.js:45)

Implement Fix

Write the code to handle edge cases and prevent failures.

if (user?.profile) console.log(user.profile.name);

Test & Verify

Run automated tests to confirm the bug is resolved.

PASS auth.test.js