@typescript-eslint/utils

What is @typescript-eslint/utils?

The @typescript-eslint/utils package provides utility functions and types that are used across the TypeScript ESLint project. It's designed to help with the development of ESLint rules, parsers, and plugins by providing a consistent set of tools for working with TypeScript code. This package is particularly useful for those creating custom ESLint rules or integrating TypeScript more deeply into their ESLint configurations.

What are @typescript-eslint/utils's main functionalities?

AST Utilities

AST Utilities provide functions to work with Abstract Syntax Tree (AST) nodes. These utilities can help in identifying node types, such as checking if a node is an identifier or a literal, which is useful when writing custom ESLint rules.

import { ASTUtils } from '@typescript-eslint/utils';
const { isIdentifier, isLiteral } = ASTUtils;

Type Checking

This feature allows rule developers to access TypeScript's type checker, enabling them to perform more sophisticated analyses, such as type inference or type checking, within their custom ESLint rules.

import { ESLintUtils } from '@typescript-eslint/utils';
const { getParserServices } = ESLintUtils;
const parserServices = getParserServices(context);
const checker = parserServices.program.getTypeChecker();

ESLint Rule Creation

Provides a utility for creating ESLint rules with a consistent structure and metadata. This is particularly useful for developers creating custom rules for projects that use TypeScript.

import { ESLintUtils } from '@typescript-eslint/utils';
const createRule = ESLintUtils.RuleCreator(name => `https://example.com/rule/${name}`);
const myRule = createRule({
  name: 'my-custom-rule',
  meta: { /* rule metadata */ },
  defaultOptions: [],
  create(context) { /* rule implementation */ }
});

Other packages similar to @typescript-eslint/utils

eslint-plugin-import

This package provides a set of ESLint rules that help ensure proper import/export syntax and order. While it focuses on module syntax, it doesn't offer TypeScript-specific utilities or type checking capabilities like @typescript-eslint/utils.

eslint-utils

Similar to @typescript-eslint/utils, eslint-utils provides utility functions for working with ESLint and AST nodes. However, it is not specifically tailored for TypeScript, lacking direct integrations with TypeScript's type system and parser.

README

@typescript-eslint/utils

Utilities for working with TypeScript + ESLint together.

👉 See https://typescript-eslint.io/packages/utils 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.

Changelog

8.18.2 (2024-12-23)

🩹 Fixes

• eslint-plugin: [no-deprecated] not reporting usages of deprecated declared constants as object value (#10498)
• eslint-plugin: [prefer-reduce-type-parameter] don't report cases in which the fix results in a type error (#10494)
• eslint-plugin: [no-unnecessary-condition] don't flag values of an unconstrained or valid type parameter (#10473)
• eslint-plugin: [consistent-indexed-object-style] use a suggestion over an auto-fix if can't reliably determine that produced index signature is valid (#10490)
• eslint-plugin: [no-unsafe-type-assertion] fix for unsafe assertion to a constrained type parameter (#10461)
• eslint-plugin: [no-unnecessary-type-arguments] handle type/value context (#10503)
• eslint-plugin: [consistent-type-assertions] allow default assertionStyle option (#10512)
• eslint-plugin: [no-unnecessary-condition] handle noUncheckedIndexedAccess true (#10514)
• typescript-eslint: export types so that declarations can be named for dts files (#10513)

❤️ Thank You

• Brad Zacher @bradzacher
• Luke Deen Taylor @controversial
• Ronen Amiel
• Scott O'Hara
• YeonJuan @yeonjuan
• Yukihiro Hasegawa @y-hsgw

You can read about our versioning strategy and releases on our website.