Improvement: useEffect/useInsertionEffect/useLayoutEffect null-check warning messages are vague and don't distinguish null vs undefined

[BalajiRKB]

Summary

The dev-mode console.warn messages for useEffect, useInsertionEffect, and useLayoutEffect in packages/react/src/ReactHooks.js are currently vague when the create callback is null or undefined.

Current Behavior

All three hooks produce this generic message:

React Hook useEffect requires an effect callback. Did you forget to pass a callback to the hook?

This message:

• Does not distinguish between null and undefined being passed
• Does not explain what the callback signature should look like
• Leaves beginners confused about what the correct fix is

Expected Behavior

The warning should:

1. Say explicitly whether null or undefined was received
2. Explain that the hook expects a function that optionally returns a cleanup function
3. Be consistent across all three effect hooks

Example improved message:

React Hook useEffect received a null effect callback. useEffect must be passed a function that optionally returns a cleanup function. Did you accidentally pass nothing or the result of a function call instead of the function itself?

Motivation

This is a very common beginner mistake — for example, passing useEffect(someAsyncFn(), []) (calling the function) instead of useEffect(someAsyncFn, []) (passing the function). A clearer error message would surface the root cause faster.

Fix

A fix has been submitted in PR #36361.

Affected Files

• packages/react/src/ReactHooks.js

[BalajiRKB]

A fix for this has been submitted in PR #36361.

The changes improve the console.warn messages in packages/react/src/ReactHooks.js for all three effect hooks to explicitly say whether null or undefined was received, and explain the expected callback signature.