You used a value that wasn't there yet
What is this error?
Something was undefined or null when your code tried to read from it. Usually data that hasn't arrived, or a name that's spelled differently than you think.
Common Causes
- Rendering data before the request finished.
- The API response shape is different from what you assumed.
- A typo in a property name.
- An array was empty and you read [0].
How to fix it (Check First)
- 1Log the whole object one line above the crash and look at what it actually contains.
- 2Add a loading state if the data is still in flight.
- 3Compare the real API response in the Network tab against your assumption.
What NOT to do
- Do not sprinkle ?. everywhere until the error stops — that hides the missing data, it doesn't supply it.
Technical Details
Property access on undefined/null throws a TypeError at runtime. Optional chaining short-circuits the access but does not resolve the absent state.