Creating ESLint Rules for eslint-cease-nonsense-rules

Overview

Creates complete ESLint rules with all required files: rule implementation, tests, documentation, and registry updates.

When to Use

• User asks to "create a new ESLint rule"
• User asks to "add a lint rule"
• User provides examples of "bad code" and "good code" for linting
• User describes behavior they want to lint against

Required Files Checklist

ALWAYS create/update ALL of these:

1. src/rules/{rule-name}.ts - Rule implementation
2. tests/rules/{rule-name}.test.ts - Test file (100% coverage required)
3. docs/rules/{rule-name}.md - Documentation
4. README.md - Add rule to appropriate category
5. src/index.ts - Register rule and export types

CONDITIONALLY update:

1. src/utilities/configure-utilities.ts - Only if rule has configurable options

Gathering Requirements

Before writing code, ask the user for:

1. Rule name (kebab-case, e.g., no-foo-bar or prefer-xyz)
2. What it detects (the bad pattern)
3. What it suggests (the good pattern)
4. Examples of incorrect code
5. Examples of correct code
6. Should it have options? If yes, what options?
7. Should it auto-fix? If yes, what's the fix?
8. What category? (Type Safety, React, Logging, Resource Management, Code Quality, Performance, Module Boundaries, TypeScript)

Implementation Patterns

Rule File Structure

See templates/rule-simple.ts.template for rules without options. See templates/rule-with-options.ts.template for rules with options.

Key points:

• Use createRule from ../utilities/create-rule
• Use AST selectors when possible (cleaner than visitor functions)
• Define type MessageIds for type-safe message IDs
• Export options interface if rule has options

Test File Structure

See templates/test.ts.template for the pattern.

Key points:

• Import describe from bun:test
• Import RuleTester from eslint
• Cover all branches for 100% coverage
• Test both valid and invalid cases
• Test options if applicable

Documentation Structure

See templates/docs.md.template for the pattern.

Key points:

• Start with # rule-name and description
• Include ## Rule Details explanation
• Include ## Options section if applicable
• Include ## Examples with ### Incorrect and ### Correct
• End with ## When Not To Use It and ## Related Rules

README.md Update

Add to appropriate category section following existing format:

#### `rule-name`

Short description of what the rule does.

**Configuration** (if options exist)

\`\`\`typescript
{
  "cease-nonsense/rule-name": ["error", { option: value }]
}
\`\`\`

**Incorrect**

\`\`\`typescript
// bad code example
\`\`\`

**Correct**

\`\`\`typescript
// good code example
\`\`\`

src/index.ts Updates

1. Add import: import ruleName from "./rules/rule-name";
2. Export type (if options): export type { RuleNameOptions } from "./rules/rule-name";
3. Add to rules object: "rule-name": ruleName,
4. Add to recommended config if it should be on by default

configure-utilities.ts Updates (if options)

Add a factory function:

export function createRuleNameOptions(options: Partial<RuleNameOptions> = {}): RuleNameOptions {
    return { defaultValue: "default", ...options };
}

Verification Checklist

Before declaring done:

• bun run typecheck passes
• bun run lint passes
• bun test passes with 100% coverage for new rule
• bun run build succeeds
• All 5+ files created/updated
• Rule appears in README under correct category
• Examples in docs match the actual rule behavior