Create Rule

Create a New ESLint Rule

Steps

1. Create the rule file: src/rules/{rule-name}.ts

import { createRule } from '../utils/createRule.js'
import { parseFnCall } from '../utils/parseFnCall.js'

export default createRule({
  create(context) {
    return {
      CallExpression(node) {
        const call = parseFnCall(context, node)
        if (!call) return
        // Rule logic here
      },
    }
  },
  meta: {
    docs: {
      description: 'Rule description',
      recommended: true,
      url: 'https://github.com/mskelton/eslint-plugin-playwright/tree/main/docs/rules/{rule-name}.md',
    },
    messages: {
      messageId: 'Error message with optional {{ interpolation }}',
    },
    schema: [],
    type: 'problem', // or 'suggestion'
    // fixable: 'code',     // add if auto-fixable
    // hasSuggestions: true, // add if suggestion-fixable
  },
})

Key utilities (all imported from ../utils/):

• parseFnCall — parse Playwright calls (test, expect, describe, hook, step, config)
• isTypeOfFnCall — check call type without full parse
• isPageMethod — check if call is page method
• getStringValue, isIdentifier, findParent, dereference — AST helpers
• replaceAccessorFixer, removePropertyFixer — fixer helpers

2. Create the test file: src/rules/{rule-name}.test.ts

import dedent from 'dedent'
import { runRuleTester } from '../utils/rule-tester.js'
import rule from './{rule-name}.js'

runRuleTester('{rule-name}', rule, {
  invalid: [
    {
      code: dedent`
        test('example', async ({ page }) => {
          // code that should trigger the rule
        })
      `,
      errors: [{ messageId: 'messageId' }],
    },
    // Global alias test
    {
      code: `it('example', () => { /* bad */ })`,
      errors: [{ messageId: 'messageId' }],
      settings: { playwright: { globalAliases: { test: ['it'] } } },
    },
  ],
  valid: [
    // code that should NOT trigger the rule
    `test('example', async ({ page }) => { /* correct usage */ })`,
  ],
})

Use runTSRuleTester (from same import) for TypeScript-specific rules.

3. Register in src/plugin.ts

Add the import (alphabetical order):

import myNewRule from './rules/{rule-name}.js'

Add to the plugin.rules object (alphabetical order):

'{rule-name}': myNewRule,

If recommended, add to sharedConfig.rules:

'playwright/{rule-name}': 'error', // or 'warn'

4. Create docs: docs/rules/{rule-name}.md

# Description of rule (`{rule-name}`)

Explain why this rule exists and what problem it prevents.

## Rule details

Examples of **incorrect** code for this rule:

\`\`\`js
// bad example
\`\`\`

Examples of **correct** code for this rule:

\`\`\`js
// good example
\`\`\`

## Options

_If rule has options, document them here. Otherwise omit this section._

5. Add to README.md rules table

Insert a row in alphabetical order in the table (around line 120+):

| [{rule-name}](https://github.com/mskelton/eslint-plugin-playwright/tree/main/docs/rules/{rule-name}.md) | Description of rule | ✅ | 🔧 | 💡 |

Leave columns blank ( ) when not applicable:

• ✅ — rule is in recommended config
• 🔧 — rule is auto-fixable (fixable: 'code')
• 💡 — rule has suggestions (hasSuggestions: true)

Verify

Run tests to confirm everything works:

yarn test <rule-name>

Source: mskelton/eslint-plugin-playwright — distributed by TomeVault.