@typescript-eslint/experimental-utils

What is @typescript-eslint/experimental-utils?

The @typescript-eslint/experimental-utils package provides various utilities for working with TypeScript and ESLint. It is part of the TypeScript ESLint project, which aims to enable ESLint to support TypeScript. The utilities in this package are considered experimental and are primarily intended for use by developers creating custom ESLint rules for TypeScript codebases.

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

AST Utilities

Provides utility functions to work with Abstract Syntax Trees (AST), such as checking if a node is an identifier.

const { ASTUtils } = require('@typescript-eslint/experimental-utils');
const { isIdentifier } = ASTUtils;

ESLint Rule Creation

Facilitates the creation of custom ESLint rules with TypeScript support, including a rule creator function that helps define metadata for rules.

const { ESLintUtils } = require('@typescript-eslint/experimental-utils');
const createRule = ESLintUtils.RuleCreator(name => `https://example.com/rule/${name}`);

Type Information

Provides utilities to retrieve type information from TypeScript code, which can be used in custom ESLint rules to perform type-aware linting.

const { TypeScriptUtils } = require('@typescript-eslint/experimental-utils');
const { getParserServices } = TypeScriptUtils;
const parserServices = getParserServices(context);
const checker = parserServices.program.getTypeChecker();

Other packages similar to @typescript-eslint/experimental-utils

eslint-plugin-import

This package provides a set of ESLint rules that help validate proper imports. It is similar to @typescript-eslint/experimental-utils in that it extends ESLint's capabilities, but it focuses specifically on import/export syntax rather than providing a general set of TypeScript utilities.

eslint-utils

Similar to @typescript-eslint/experimental-utils, eslint-utils provides utility functions for working with ESLint and ASTs. However, it is not specifically tailored to TypeScript and does not provide type information utilities.

tsutils

Tsutils is a utility library that provides functions for working with TypeScript's AST and type checker. While it offers some similar functionality to @typescript-eslint/experimental-utils, it is not designed specifically for creating ESLint rules and does not integrate with ESLint out of the box.

README

Utils for ESLint Plugins

Utilities for working with TypeScript + ESLint together.

Note

This package has inherited its version number from the @typescript-eslint project. Meaning that even though this package is 2.x.y, you shouldn't expect 100% stability between minor version bumps. i.e. treat it as a 0.x.y package.

Feel free to use it now, and let us know what utilities you need or send us PRs with utilities you build on top of it.

Once it is stable, it will be renamed to @typescript-eslint/util for a 4.0.0 release.

Exports

Name	Description
ASTUtils	Tools for operating on the ESTree AST. Also includes the eslint-utils package, correctly typed to work with the types found in TSESTree
ESLintUtils	Tools for creating ESLint rules with TypeScript.
JSONSchema	Types from the @types/json-schema package, re-exported to save you having to manually import them. Also ensures you're using the same version of the types as this package.
TSESLint	Types for ESLint, correctly typed to work with the types found in TSESTree.
TSESLintScope	The eslint-scope package, correctly typed to work with the types found in both TSESTree and TSESLint
TSESTree	Types for the TypeScript flavor of ESTree created by @typescript-eslint/typescript-estree.
AST_NODE_TYPES	An enum with the names of every single node found in TSESTree.
AST_TOKEN_TYPES	An enum with the names of every single token found in TSESTree.
ParserServices	Typing for the parser services provided when parsing a file using @typescript-eslint/typescript-estree.

Contributing

See the contributing guide here

Changelog

4.33.0 (2021-10-04)

Bug Fixes

• eslint-plugin: [lines-between-class-members] fix exceptAfterOverload for abstract methods (#3943) (240fc65)
• eslint-plugin: [no-confusing-void-expression] support optional chaining (#3937) (c40dd13)
• eslint-plugin: [no-restricted-imports] fix crash when no options given (#3947) (edaa3c1)
• eslint-plugin: [non-nullable-type-assertion-style] false-positive with non-nullish as assertions and types (#3940) (40760f9)
• eslint-plugin: [padding-line-between-statements] TSModuleBlock should change scope (#3944) (f8f534e)
• eslint-plugin: [prefer-regexp-exec] check RegExp without flags (#3946) (0868725)
• experimental-utils: add getPhysicalFilename() to RuleContext (#3934) (ee5dfd4)
• experimental-utils: require fix in suggestions (#3949) (f022fb1)

Features

• experimental-utils: extract isNodeOfTypeWithConditions out of ast-utils' predicates (#3837) (214f898)