typescript-eslint

What is typescript-eslint?

typescript-eslint is a set of tools that allows you to use ESLint to lint TypeScript code. It provides a parser that can read TypeScript code and a set of rules that are specific to TypeScript, enabling you to enforce coding standards and catch potential issues in your TypeScript projects.

What are typescript-eslint's main functionalities?

Linting TypeScript Code

This configuration file sets up ESLint to use the TypeScript parser and includes recommended rules from the @typescript-eslint plugin. It also adds a custom rule to error on unused variables.

module.exports = {
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint'],
  extends: [
    'eslint:recommended',
    'plugin:@typescript-eslint/recommended'
  ],
  rules: {
    '@typescript-eslint/no-unused-vars': 'error'
  }
};

Type-Aware Rules

This configuration enables type-aware linting rules by specifying a TypeScript project. The rule '@typescript-eslint/no-floating-promises' ensures that promises are properly handled.

module.exports = {
  parser: '@typescript-eslint/parser',
  parserOptions: {
    project: './tsconfig.json'
  },
  plugins: ['@typescript-eslint'],
  extends: [
    'plugin:@typescript-eslint/recommended-requiring-type-checking'
  ],
  rules: {
    '@typescript-eslint/no-floating-promises': 'error'
  }
};

Custom Rules

This configuration enforces explicit return types on functions, but allows expressions to omit the return type. This helps in maintaining clear and predictable function signatures.

module.exports = {
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint'],
  rules: {
    '@typescript-eslint/explicit-function-return-type': ['error', {
      allowExpressions: true
    }]
  }
};

Other packages similar to typescript-eslint

tslint

TSLint is an extensible static analysis tool that checks TypeScript code for readability, maintainability, and functionality errors. However, TSLint has been deprecated in favor of ESLint and typescript-eslint, as the latter provides a more flexible and extensible architecture.

eslint

ESLint is a widely-used linting tool for JavaScript. While it does not natively support TypeScript, it can be extended with the typescript-eslint parser and plugin to lint TypeScript code. This makes ESLint a versatile tool for projects that use both JavaScript and TypeScript.

prettier

Prettier is an opinionated code formatter that supports multiple languages, including TypeScript. While it is not a linter, it can be used alongside typescript-eslint to ensure consistent code formatting. Prettier focuses on code style, whereas typescript-eslint focuses on code quality and potential errors.

README

typescript-eslint

Tooling which enables you to use TypeScript with ESLint

👉 See https://typescript-eslint.io/packages/typescript-eslint for documentation on this package.

See https://typescript-eslint.io for general documentation on typescript-eslint, the tooling that allows you to run ESLint and Prettier on TypeScript code.