useHookAtTopLevel

JSX and TSX

Summary

• Rule available since: v1.0.0
• Diagnostic Category: lint/correctness/useHookAtTopLevel
• This rule doesn’t have a fix.
• The default severity of this rule is error.
• This rule belongs to the following domains:
  • react
  • next
• Sources:
  • Same as react-hooks/rules-of-hooks

How to configure

biome.json

{
  "linter": {
    "rules": {
      "correctness": {
        "useHookAtTopLevel": "error"
      }
    }
  }
}

Description

Enforce that all React hooks are being called from the Top Level component functions.

This rule should be used only in React projects.

To understand why this required see https://reactjs.org/docs/hooks-rules.html#only-call-hooks-at-the-top-level

Examples

Invalid

function Component1({ a }) {
    if (a == 1) {
        useEffect();
    }
}

code-block.js:3:9 lint/correctness/useHookAtTopLevel ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ This hook is being called conditionally, but all hooks must be called in the exact same order in every component render.
  
    1 │ function Component1({ a }) {
    2 │     if (a == 1) {
  > 3 │         useEffect();
      │         ^^^^^^^^^
    4 │     }
    5 │ }
  
  ℹ For React to preserve state between calls, hooks needs to be called unconditionally and always in the same order.
  
  ℹ See https://react.dev/reference/rules/rules-of-hooks
  

function Component1({ a }) {
    if (a != 1) {
        return;
    }

    useEffect();
}

code-block.js:6:5 lint/correctness/useHookAtTopLevel ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ This hook is being called conditionally, but all hooks must be called in the exact same order in every component render.
  
    4 │     }
    5 │ 
  > 6 │     useEffect();
      │     ^^^^^^^^^
    7 │ }
    8 │ 
  
  ℹ Hooks should not be called after an early return.
  
    1 │ function Component1({ a }) {
  > 2 │     if (a != 1) {
      │                  
  > 3 │         return;
      │         ^^^^^^^
    4 │     }
    5 │ 
  
  ℹ For React to preserve state between calls, hooks needs to be called unconditionally and always in the same order.
  
  ℹ See https://react.dev/reference/rules/rules-of-hooks
  

function notAHook() {
    useEffect();
}

code-block.js:2:5 lint/correctness/useHookAtTopLevel ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ This hook is being called from within a function or method that is not a hook or component.
  
    1 │ function notAHook() {
  > 2 │     useEffect();
      │     ^^^^^^^^^
    3 │ }
    4 │ 
  
  ℹ Move the hook call into the top level of a hook or component in order to use it.
  
  ℹ See https://react.dev/reference/rules/rules-of-hooks
  

Valid

function Component1() {
    useEffect();
}

test("the hook", () => {
    renderHook(() => useHook());
});

Related links

• Disable a rule
• Configure the code fix
• Rule options
• Source Code
• Test Cases