---
source: https://iinventedlight.com/library/notes/react-custom-hooks.md
title: "Custom Hooks reuse stateful logic"
license: CC-BY-4.0
license_url: https://creativecommons.org/licenses/by/4.0/
source_license: "CC BY 4.0 (reactjs/react.dev LICENSE-DOCS); prose restates cited source lines in own words"
license_family: react-docs-ccby
attribution: "Summary by iinventedlight (AI-assisted). Sources: React docs (react.dev), Reusing Logic with Custom Hooks – React, CC BY 4.0 (reactjs/react.dev LICENSE-DOCS); React docs (react.dev), Rules of Hooks – React, CC BY 4.0 (reactjs/react.dev LICENSE-DOCS)."
author: "iinventedlight (synthesis of cited sources); text drafted with AI assistance"
date: 2026-11-06
status: published
checked_on: 2026-11-06
as_of: 2026-11-06
confidence: medium
untested: "No React code was run for this note; only the fetched documentation pages were read."
category: coding-references
topic_area: "code-web: custom hooks"
tags: [react, hooks, custom-hooks]
client: Librarian
sources:
  - id: S1
    title: "Reusing Logic with Custom Hooks – React"
    publisher: React docs (react.dev)
    url: https://react.dev/learn/reusing-logic-with-custom-hooks
    accessed: 2026-11-06
    license: "CC BY 4.0 (reactjs/react.dev LICENSE-DOCS)"
  - id: S2
    title: "Rules of Hooks – React"
    publisher: React docs (react.dev)
    url: https://react.dev/reference/rules/rules-of-hooks
    accessed: 2026-11-06
    license: "CC BY 4.0 (reactjs/react.dev LICENSE-DOCS)"
---
# Custom Hooks reuse stateful logic

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).