Fix “map is not a function” Quickly

If you get:

map is not a function

the problem is usually not with map itself.

The real issue is that the value before .map() is not an array.

Quick fix checklist:

1. Log the value before mapping
2. Confirm the API really returns an array
3. Add a safe fallback

Example:
const items = Array.isArray(data) ? data : [];
items.map(item => ...)

Common causes:

• API returned an object instead of a list
• Initial state was set to null or {}
• Nested response path was wrong
• Data was not loaded yet

Safe default:
Always initialize list state as [] when you expect arrays.

That one small default fixes a surprising number of UI crashes.