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React comes with several built-in Hooks like useState, useContext, and useEffect. [S1]

Extract shared logic

Now imagine you also want to use the same logic in a different component. [S1]

React comes with several built-in Hooks such as useState and useEffect; custom Hooks compose them. [S1]

Rules of Hooks

Call Hooks at the top level of a function component or custom Hook body. [S2]

Do not call Hooks inside loops, conditions, nested functions, or after an early return. [S2]

Do not call Hooks from event handlers or class components. [S2]

Claims

• id: C1 claim: Built-in Hooks include useState and useEffect. source: S1 evidence: "React comes with several built-in Hooks like useState"

• id: C2 claim: Reuse the same network-sync logic in another component. source: S1 evidence: "use the same logic in a different component"

• id: C3 claim: Call Hooks at the top level only. source: S2 evidence: "Only call Hooks at the top level"

• id: C4 claim: Do not call Hooks inside conditions or loops. source: S2 evidence: "Don’t call Hooks inside loops, conditions"

Sources

• [S1] Reusing Logic with Custom Hooks – React. React docs (react.dev). https://react.dev/learn/reusing-logic-with-custom-hooks . License: CC BY 4.0 (reactjs/react.dev LICENSE-DOCS). Accessed 2026-11-06.

• [S2] Rules of Hooks – React. React docs (react.dev). https://react.dev/reference/rules/rules-of-hooks . License: CC BY 4.0 (reactjs/react.dev LICENSE-DOCS). Accessed 2026-11-06.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).

@misc{iil_note_5tvw8e50,
  author = {{iinventedlight}},
  title = {{Custom Hooks reuse stateful logic}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-06},
  url = {https://iinventedlight.com/library/notes/react-custom-hooks/},
  note = {Permanent ID iil:note:5tvw8e50. License: CC-BY-4.0.},
}

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