How to fix @typescript-eslint rule 'X' requires parser in TypeScript

What this error means

The "@typescript-eslint rule requires parser" error happens when you enable ESLint rules that need TypeScript's type system to work, but your ESLint configuration doesn't tell the parser how to access TypeScript's type information. Rules like @typescript-eslint/no-floating-promises, @typescript-eslint/no-misused-promises, and @typescript-eslint/await-thenable require type information to analyze your code correctly. TypeScript-ESLint has two modes: syntactic rules (which only need to parse the code structure) and type-aware rules (which need full TypeScript type information). Type-aware rules are more powerful because they can catch semantic errors that purely syntactic analysis would miss, but they require additional configuration. The full error message typically says: "You have used a rule which requires parserServices to be generated. You must therefore provide a value for the 'parserOptions.project' property for @typescript-eslint/parser." This means ESLint needs to know where your tsconfig.json is located so it can create a TypeScript program with full type information.

Typical symptoms

• ESLint fails with 'rule requires parserServices to be generated' message
• Error mentions specific @typescript-eslint rules like no-floating-promises or strict-boolean-expressions
• Message states 'parserOptions.project' or 'parserOptions.projectService' must be configured
• Linting works for some rules but fails when type-aware rules are enabled
• Error occurs after adding typed-linting rules from @typescript-eslint/eslint-plugin
• VS Code ESLint extension shows errors but syntax highlighting works fine

Common causes

1. Using type-aware @typescript-eslint rules without configuring parserOptions
2. Missing parserOptions.projectService or parserOptions.project in ESLint config
3. ESLint config doesn't specify @typescript-eslint/parser as the parser
4. tsconfig.json not found in the expected location relative to ESLint config
5. Using typed rules in files not included in tsconfig.json
6. Outdated @typescript-eslint packages that don't support projectService
7. Attempting to lint files outside the TypeScript project scope

How to fix "@typescript-eslint rule 'X' requires parser"

// .eslintrc.js or eslint.config.js
module.exports = {
  parser: '@typescript-eslint/parser',
  parserOptions: {
    projectService: true,
    tsconfigRootDir: __dirname,
  },
  plugins: ['@typescript-eslint'],
  extends: [
    'eslint:recommended',
    'plugin:@typescript-eslint/recommended',
    'plugin:@typescript-eslint/recommended-requiring-type-checking',
  ],
};

// eslint.config.js
import tseslint from '@typescript-eslint/eslint-plugin';
import parser from '@typescript-eslint/parser';

export default [
  {
    files: ['**/*.ts', '**/*.tsx'],
    languageOptions: {
      parser: parser,
      parserOptions: {
        projectService: true,
        tsconfigRootDir: import.meta.dirname,
      },
    },
    plugins: { '@typescript-eslint': tseslint },
    rules: tseslint.configs['recommended-requiring-type-checking'].rules,
  },
];

// .eslintrc.js
module.exports = {
  parser: '@typescript-eslint/parser',
  parserOptions: {
    project: './tsconfig.json',
    tsconfigRootDir: __dirname,
  },
  plugins: ['@typescript-eslint'],
  extends: [
    'plugin:@typescript-eslint/recommended-requiring-type-checking',
  ],
};

module.exports = {
  parser: '@typescript-eslint/parser',
  parserOptions: {
    project: [
      './tsconfig.json',
      './packages/*/tsconfig.json',
    ],
    tsconfigRootDir: __dirname,
  },
};

module.exports = {
  parser: '@typescript-eslint/parser',
  parserOptions: {
    project: true,
    tsconfigRootDir: __dirname,
  },
};

// tsconfig.json
{
  "compilerOptions": {
    "strict": true,
    // ... other options
  },
  "include": [
    "src/**/*",
    "tests/**/*",
    "*.config.ts"
  ],
  "exclude": [
    "node_modules",
    "dist",
    "build"
  ]
}

// tsconfig.eslint.json
{
  "extends": "./tsconfig.json",
  "include": [
    "src/**/*",
    "tests/**/*",
    "*.config.ts",
    ".eslintrc.ts"
  ]
}

module.exports = {
  parserOptions: {
    project: './tsconfig.eslint.json',
  },
};

# Check current versions
npm list @typescript-eslint/parser @typescript-eslint/eslint-plugin

# Update to latest versions
npm install --save-dev @typescript-eslint/parser@latest @typescript-eslint/eslint-plugin@latest

# Or with specific versions (v7+ recommended)
npm install --save-dev @typescript-eslint/parser@^7.0.0 @typescript-eslint/eslint-plugin@^7.0.0

npm install --save-dev typescript@latest

// .eslintrc.js
module.exports = {
  parser: '@typescript-eslint/parser',
  parserOptions: {
    projectService: true,
    tsconfigRootDir: __dirname,
  },
  overrides: [
    {
      // Disable type-aware rules for config files
      files: ['*.config.js', '.eslintrc.js'],
      parserOptions: {
        projectService: false,
      },
      rules: {
        '@typescript-eslint/no-floating-promises': 'off',
        '@typescript-eslint/no-misused-promises': 'off',
      },
    },
  ],
};

// .eslintrc.js
module.exports = {
  ignorePatterns: ['*.config.js', 'scripts/*.js'],
  // ... rest of config
};

// .eslintrc.js - CORRECT
module.exports = {
  parser: '@typescript-eslint/parser',  // ✓ Required
  parserOptions: {
    projectService: true,
  },
};

// WRONG - missing parser
module.exports = {
  parserOptions: {
    projectService: true,  // ✗ Won't work without parser
  },
};

// eslint.config.js - CORRECT
import parser from '@typescript-eslint/parser';

export default [
  {
    languageOptions: {
      parser: parser,  // ✓ Required
      parserOptions: {
        projectService: true,
      },
    },
  },
];

# Remove ESLint cache
rm -rf .eslintcache
rm -rf node_modules/.cache/eslint

# Re-run ESLint
npx eslint . --fix

Advanced notes

module.exports = {
  overrides: [
    {
      files: ['src/**/*.ts'],
      parserOptions: { projectService: true },
      extends: ['plugin:@typescript-eslint/recommended-requiring-type-checking'],
    },
    {
      files: ['tests/**/*.ts'],
      parserOptions: { projectService: false },  // Faster for tests
    },
  ],
};

# See which files TypeScript is compiling
npx tsc --listFiles

# Trace module resolution
npx tsc --traceResolution | grep tsconfig

DEBUG=eslint:cli-engine npx eslint src/

// Root .eslintrc.js
module.exports = {
  parser: '@typescript-eslint/parser',
  parserOptions: {
    // Option 1: Auto-detect (recommended)
    project: true,
    tsconfigRootDir: __dirname,

    // Option 2: Explicit paths
    // project: [
    //   './tsconfig.json',
    //   './packages/*/tsconfig.json',
    //   './apps/*/tsconfig.json',
    // ],
  },
};

// packages/my-package/.eslintrc.js
module.exports = {
  extends: '../../.eslintrc.js',
  parserOptions: {
    project: './tsconfig.json',
    tsconfigRootDir: __dirname,
  },
};

// eslint.config.js
import tseslint from 'typescript-eslint';

export default tseslint.config(
  {
    languageOptions: {
      parserOptions: {
        projectService: true,
        tsconfigRootDir: import.meta.dirname,
      },
    },
  },
  ...tseslint.configs.recommendedTypeChecked,
);

Frequently asked questions

What does "@typescript-eslint rule 'X' requires parser" mean?

The "@typescript-eslint rule requires parser" error happens when you enable ESLint rules that need TypeScript's type system to work, but your ESLint configuration doesn't tell the parser how to access TypeScript's type information. Rules like @typescript-eslint/no-floating-promises, @typescript-eslint/no-misused-promises, and @typescript-eslint/await-thenable require type information to analyze your code correctly. TypeScript-ESLint has two modes: syntactic rules (which only need to parse the code structure) and type-aware rules (which need full TypeScript type information).

How do I fix "@typescript-eslint rule 'X' requires parser"?

This error occurs when using a @typescript-eslint rule that needs type information but the ESLint parser isn't configured to provide it. You need to configure parserOptions.projectService or parserOptions.project in your ESLint config to enable typed linting.

What causes "@typescript-eslint rule 'X' requires parser"?

Using type-aware @typescript-eslint rules without configuring parserOptions Missing parserOptions.projectService or parserOptions.project in ESLint config ESLint config doesn't specify @typescript-eslint/parser as the parser

Is the "@typescript-eslint rule 'X' requires parser" error serious?

It is a medium-severity error — more of a blocker than a risk. The steps above resolve it.

Related errors

• Type information for @typescript-eslint rule unavailable

  How to fix 'Type information for @typescript-eslint rule unavailable' error

  MEDIUM

• Cannot resolve TypeScript service in @typescript-eslint

  How to fix 'Cannot resolve TypeScript service in @typescript-eslint' error

  MEDIUM

• 'esModuleInterop' and 'allowSyntheticDefaultImports' require module resolution

  'esModuleInterop' and 'allowSyntheticDefaultImports' require module resolution

  MEDIUM

• @typescript-eslint parser requires TypeScript service

  @typescript-eslint parser requires TypeScript service

  MEDIUM

• Cannot find name 'process'. Do you need to install type definitions for node? Try `npm i --save-dev @types/node` and then add 'node' to the types field in your tsconfig.

  How to fix "Cannot find name 'process'" in TypeScript

  MEDIUM

• Module has no exported member 'X'

  How to fix 'Module has no exported member X' error in TypeScript

  MEDIUM

Official resources & further reading

• 📚TypeScript Official Documentation
• 📖
  typescript-eslint - Parser Documentation(Official Docs)
• 📖
  typescript-eslint - Typed Linting Setup(Official Docs)
• 📖
  typescript-eslint - Troubleshooting FAQs(Official Docs)
• Jacob Paris - Solve parserOptions.project Bug
• typescript-eslint - parserOptions.project = true
• 📖
  ESLint - Configure a Parser(Official Docs)
• 🐙
  TypeScript ESLint - parserServices Issues(GitHub)