javascriptNull / UndefinedHard

Optional chaining only guards the first link

Time: 0:00

What it should do

cityOf(user) should return the user's city, or "unknown" if any part of the path is missing.

What goes wrong

cityOf(null) returns "unknown" as expected, but cityOf({}) throws "Cannot read properties of undefined (reading 'city')".

Hints

This is a null and undefined errors bug

Cannot read properties of undefined, NoneType has no attribute, NaN appearing from nowhere.