@typescript-eslint/types 8.x

Complete instructions

Verified against @typescript-eslint/types@8.70.0 on 2026-09-08. 2 of 2 examples executed.

@typescript-eslint/types v8

What this package is

@typescript-eslint/types is an internal package containing TypeScript-ESTree AST specifications and related declarations. The v8 entrypoint re-exports:

• AST_NODE_TYPES and AST_TOKEN_TYPES from the generated AST specification
• declarations from lib
• parser options
• TypeScript-ESTree declarations

The package README describes it as an internal package used to reduce dependency cycles and provide lighter-weight runtime packages. It is probably not the public entry point for application code.

This package does not provide a documented parser, CLI, runner, build-step API, or standalone workflow. A plain script can use its runtime enums and type declarations, but parsing and tool execution belong to the surrounding TypeScript-ESLint tooling.

Runtime enums

AST_NODE_TYPES contains values used by AST node type properties. AST_TOKEN_TYPES contains values used by AST token type properties.

Known values include:

AST_NODE_TYPES.Identifier === 'Identifier'
AST_NODE_TYPES.TSInterfaceDeclaration === 'TSInterfaceDeclaration'
AST_TOKEN_TYPES.Identifier === 'Identifier'
AST_TOKEN_TYPES.Punctuator === 'Punctuator'

Use the enum values rather than repeating string literals when checking these discriminants.

import assert from 'node:assert/strict';
import { AST_NODE_TYPES, AST_TOKEN_TYPES } from '@typescript-eslint/types';

assert.equal(AST_NODE_TYPES.Identifier, 'Identifier');
assert.equal(AST_NODE_TYPES.TSInterfaceDeclaration, 'TSInterfaceDeclaration');
assert.equal(AST_TOKEN_TYPES.Identifier, 'Identifier');
assert.equal(AST_TOKEN_TYPES.Punctuator, 'Punctuator');

Parser option declarations

ParserOptions is exported as a type. It supports, among other properties, ecmaFeatures, ecmaVersion, JSX-related settings, TypeScript decorator and diagnostic settings, project settings, source type, token/range settings, and additional unknown properties through its index signature.

The documented v8 declaration includes these important project-related shapes:

• project?: string[] | string | boolean | null
• projectService?: boolean | ProjectServiceOptions
• programs?: Program[] | null
• filePath?: string
• tsconfigRootDir?: string
• extraFileExtensions?: string[]
• cacheLifetime?: { glob?: CacheDurationSeconds }

ProjectServiceOptions is also exported as a type. Its fields are:

• allowDefaultProject?: string[]
• defaultProject?: string
• maximumDefaultProjectFileMatchCount_THIS_WILL_SLOW_DOWN_LINTING?: number

The following is a type-checking example only; this package does not consume the options or start a project service itself.

import assert from 'node:assert/strict';
import type { ParserOptions, ProjectServiceOptions } from '@typescript-eslint/types';

const projectService: ProjectServiceOptions = {
  allowDefaultProject: ['*.js'],
  defaultProject: 'tsconfig.json',
  maximumDefaultProjectFileMatchCount_THIS_WILL_SLOW_DOWN_LINTING: 8,
};

const options = {
  filePath: 'example.ts',
  project: 'tsconfig.json',
  projectService,
  ecmaFeatures: { jsx: true },
  tokens: true,
  range: true,
} satisfies ParserOptions;

assert.equal(options.projectService.defaultProject, 'tsconfig.json');
assert.equal(options.ecmaFeatures.jsx, true);

v8 migration traps

Do not copy an older AST parent assumption

The v8 changelog calls out stricter parent types for the AST. Code written against an older major may assume a broader or less precise parent shape. Update AST visitors and type narrowing to satisfy the v8 declarations instead of forcing older parent assumptions through casts.

Use projectService, not the experimental older name

The v8 changelog says the experimental project-service option was stabilized as projectService, and that EXPERIMENTAL_useSourceOfProjectReferenceRedirect was removed. Do not carry those experimental option names into v8 ParserOptions configuration.

projectService may be a boolean or a ProjectServiceOptions object. The object form is supported by v8 types; it is not evidence that this package starts or configures the service by itself.

Do not treat this package as the parser

The package exports declarations and the two runtime enums. It does not document a parsing function or a command to execute a parser. A direct script can assert enum values or type-check option-shaped data, as shown above, but parsing, linting, and project-service behavior must be exercised through the tool that owns those workflows.

What this skill does not cover

• Parsing source text into an AST
• Traversing or visiting ASTs
• Running ESLint or a TypeScript-ESLint parser
• Starting or configuring a project service at runtime
• The complete member list or exact declarations of every re-exported AST type
• The concrete allowed values of the exported type aliases EcmaVersion, SourceType, JSDocParsingMode, DebugLevel, and CacheDurationSeconds
• Public-package recommendations beyond the package's documented internal-package warning