prefer_use_prefix

v0.4.0 Warning Fix Hook Rules

Flags functions and methods that call hooks internally but do not follow the use prefix naming convention. Custom hooks must start with use (or _use for private functions) so that the hooks framework and other lint rules can identify them as hooks.

Why use this rule

The use prefix is a critical convention in the hooks ecosystem. Without it, lint rules like avoid_conditional_hooks cannot detect that a function is a hook, leading to missed warnings. Consistent naming also helps developers immediately recognize hook functions in code review.

See also: flutter_hooks - Custom hooks

Don’t

// Top-level function calling hooks without 'use' prefix
String myCustomHook() {
  return useMemoized(() => 'hello');
}

// Private function without '_use' prefix
ValueNotifier<int> _myPrivateHook() {
  return useState(0);
}

class BadWidget extends HookWidget {
  ValueNotifier<int> _fetchData() {
    return useState(42);
  }

  @override
  Widget build(BuildContext context) {
    final data = _fetchData();
    return Text('$data');
  }
}

Do

// Top-level function with 'use' prefix
String useCustomHook() {
  return useMemoized(() => 'hello');
}

// Private function with '_use' prefix
int _usePrivateHook() {
  return useState(0);
}

class GoodWidget extends HookWidget {
  int _useData() {
    return useState(42);
  }

  @override
  Widget build(BuildContext context) {
    final data = _useData();
    return Text('$data');
  }
}

// Regular functions that don't call hooks need no prefix:
int regularFunction() => 42;

Configuration

This rule is in the pedantic preset, so it is enabled by preset: pedantic or by name:

many_lints.yaml

rules:
  prefer_use_prefix: true

To turn it off again:

many_lints.yaml

rules:
  prefer_use_prefix: false

To keep the rule on but skip certain paths, use per-rule exclude.

Related rules

• prefer_use_callback — Use ‘useCallback’ instead of ‘useMemoized’ for memoizing functions.
• avoid_hooks_outside_build — Only call hooks from a hook context.
• avoid_misused_hooks — Don’t call hooks inside loops.
• avoid_unnecessary_enum_prefix — Drop an enum name repeated in its own constants.