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React

958What Makes a Custom Hook
959Identifying Reusable Logic
960Your First Custom Hook: useToggle
961Extracting Form Input Logic
962Extracting Fetch Logic
963Passing Parameters to Custom Hooks
964Returning Values from Custom Hooks
965Custom Hooks Can Use Multiple Built-in Hooks
966useLocalStorage Example
967useDebounce Example
968Extracting Event Listener Logic
969When NOT to Extract
970Custom Hooks vs Utility Functions
971The Two Cardinal Rules of Hooks
972Why Hooks Must Be Called in Order
973Top Level: No Conditionals, No Loops
974Early Returns After Hooks Are Forbidden
975Only React Functions Can Call Hooks
976The Custom Hook Naming Convention: useX
977Conditional Logic Around Hook Results, Not Calls
978Multiple Hooks of the Same Type Are Fine
979Dynamic Hook Counts Break Everything
980Hooks in Callbacks and Event Handlers
981The Mental Model: Hook Array Indexing
982Why Custom Hooks Must Start with 'use'
983The useX Naming Pattern
984What Happens Without the 'use' Prefix
985Naming for Clarity and Intent
986Non-Hook Helper Functions
987Consistency Across Your Codebase
988Composing Multiple Hooks in a Custom Hook
989Building Higher-Order Hooks
990useLocalStorage: Combining useState with useEffect
991useDebounce: Composing useState with useEffect Cleanup
992Extracting Shared Logic from Multiple Custom Hooks
993Composing Third-Party Hooks
994Hook Composition vs Function Composition
995Avoiding Over-Abstraction in Hook Composition
996Testing Composed Custom Hooks
997The Signal: When Logic is Repeated Across Components
998The Cost of Premature Extraction
999The Three-Strike Rule for Hook Extraction
1000When Single-Component Logic Should Stay Inline

React

958What Makes a Custom Hook
959Identifying Reusable Logic
960Your First Custom Hook: useToggle
961Extracting Form Input Logic
962Extracting Fetch Logic
963Passing Parameters to Custom Hooks
964Returning Values from Custom Hooks
965Custom Hooks Can Use Multiple Built-in Hooks
966useLocalStorage Example
967useDebounce Example
968Extracting Event Listener Logic
969When NOT to Extract
970Custom Hooks vs Utility Functions
971The Two Cardinal Rules of Hooks
972Why Hooks Must Be Called in Order
973Top Level: No Conditionals, No Loops
974Early Returns After Hooks Are Forbidden
975Only React Functions Can Call Hooks
976The Custom Hook Naming Convention: useX
977Conditional Logic Around Hook Results, Not Calls
978Multiple Hooks of the Same Type Are Fine
979Dynamic Hook Counts Break Everything
980Hooks in Callbacks and Event Handlers
981The Mental Model: Hook Array Indexing
982Why Custom Hooks Must Start with 'use'
983The useX Naming Pattern
984What Happens Without the 'use' Prefix
985Naming for Clarity and Intent
986Non-Hook Helper Functions
987Consistency Across Your Codebase
988Composing Multiple Hooks in a Custom Hook
989Building Higher-Order Hooks
990useLocalStorage: Combining useState with useEffect
991useDebounce: Composing useState with useEffect Cleanup
992Extracting Shared Logic from Multiple Custom Hooks
993Composing Third-Party Hooks
994Hook Composition vs Function Composition
995Avoiding Over-Abstraction in Hook Composition
996Testing Composed Custom Hooks
997The Signal: When Logic is Repeated Across Components
998The Cost of Premature Extraction
999The Three-Strike Rule for Hook Extraction
1000When Single-Component Logic Should Stay Inline

← React

Lesson 971 of 2,396·25. Custom HooksPro lesson

The Two Cardinal Rules of Hooks

Only call hooks at the top level and only call hooks from React functions—the foundational constraints.

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