eslint-plugin-what

ESLint rules for What Framework. Catches common signal bugs and enforces framework patterns. Designed for ESLint 9+ flat config.

Install

npm install eslint-plugin-what --save-dev

Requires ESLint 9 or later.

Setup

// eslint.config.js
import what from 'eslint-plugin-what';

export default [
  what.configs.recommended,
];

Configs

| Config | Description | |---|---| | what.configs.recommended | Balanced rules as warnings | | what.configs.strict | All rules as errors + prefer-set | | what.configs.compiler | For projects using the What compiler (disables rules the compiler handles) |

Rules

what/no-signal-in-effect-deps

Prevents passing signal getters as effect dependencies. Signals are already reactive -- including them in deps arrays causes effects to re-run on every render.

// Bad
useEffect(() => { ... }, [count()]);

// Good
useEffect(() => { ... }, []);

what/reactive-jsx-children

Ensures dynamic values in JSX are wrapped in reactive functions so they update when signals change.

// Bad - won't update
<p>{count()}</p>

// Good
<p>{() => count()}</p>

what/no-signal-write-in-render

Prevents writing to signals during component render, which can cause infinite re-render loops.

// Bad
function App() {
  count.set(5); // writing during render
  return <p>{count()}</p>;
}

// Good
function App() {
  useEffect(() => { count.set(5); }, []);
  return <p>{() => count()}</p>;
}

what/no-camelcase-events

Enforces lowercase event handler names (onclick instead of onClick). What Framework uses lowercase events natively.

// Bad
<button onClick={handler}>

// Good
<button onclick={handler}>

what/prefer-set

Suggests using signal.set() instead of reassignment for signal updates. Off by default.

Config Details

recommended

{
  'what/no-signal-in-effect-deps': 'warn',
  'what/reactive-jsx-children': 'warn',
  'what/no-signal-write-in-render': 'warn',
  'what/no-camelcase-events': 'warn',
  'what/prefer-set': 'off',
}

strict

{
  'what/no-signal-in-effect-deps': 'error',
  'what/reactive-jsx-children': 'error',
  'what/no-signal-write-in-render': 'error',
  'what/no-camelcase-events': 'error',
  'what/prefer-set': 'warn',
}

compiler

{
  'what/no-signal-in-effect-deps': 'warn',
  'what/reactive-jsx-children': 'off',       // compiler handles reactive wrapping
  'what/no-signal-write-in-render': 'warn',
  'what/no-camelcase-events': 'off',          // compiler normalizes events
  'what/prefer-set': 'off',
}

Links

• Documentation
• GitHub

License

MIT