Moderate React Question 99 of 229

What are the rules of hooks?

Frontend Master · Speak this in 60–90 seconds · Faridabad & Delhi NCR

PICTURE THIS: REACT RENDER CYCLE

State changesetState / hook
ReconcileVirtual DOM diff
CommitUpdate real DOM

Simple meaning

Only call hooks at the top level of a React function, not in loops or conditions, so the order stays stable.

1

WHY — React instead of guessing?

Why interviewers care about React:

React questions separate people

who only read docs from people who shipped.

Keep it short, concrete,

and tied to Frontend work.

Stay structured

Name the idea, why it exists, then one short example.

Close cleanly

End with when you use it and one common pitfall.

2

STEPS — What happens step by step?

Before you speak the answer, walk the interviewer through these steps:

  1. 1
    Only call hooks at

    the top level of a React function, not in loops or conditions, so the order stays stable.

  2. 2
    Only call them from

    React functions or custom hooks.

  3. 3
    Breaking the order desyncs

    state between renders, which is why the linter is not optional.

  4. 4
    Give an example

    One tiny concrete case you can say aloud.

  5. 5
    Common mistake

    What juniors usually get wrong.

  6. 6
    Close

    When you pick this over the alternative.

3

EXAMPLE — See it in action

Here's a short line you can speak, broken into clear beats:

Say this line
“Only call them from React functions or custom hooks.”
Break into beats
OnlycallthemfromReactfunctions
Speaking order
2987408337471632900

Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.

Key takeaway

Only call hooks at the top level of a React function, not in loops or conditions, so the order stays stable. Only call them from React functions or custom hooks.

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