FrontEnd

Question 1

useMemo

Answer 1

“caches” data that is not necessary to recalculate during state update due to it’s value not changing.
It does create a memory overhead by storing said values.

Use cases:
- preventing a slow function from being recreated
- avoids reference comparison of data that doesn’t change.

Returns: outcome of function

Question 2

useCallback

Answer 2

“caches” a function that doesn’t need recreation on component re-render.

Use cases:
- prevent a function from being recreated when not necessary

Returns: whole function