eslint-scope

9.1.2 verified Sat Apr 25 auth: no javascript

ESLint Scope is the ECMAScript scope analyzer used in ESLint, forked from escope. The current stable version is 9.1.2, with regular releases as part of the ESLint monorepo. It analyzes ESTree-compliant ASTs to produce a ScopeManager with variable scopes, references, and definitions. Key differentiators include deep integration with ESLint, support for JSX, modern ECMAScript features, and both ESM and CommonJS module analysis. It ships with TypeScript types since v9.1.0 and requires Node.js ^20.19.0 || ^22.13.0 || >=24.

Common errors

error TypeError: eslintScope.analyze is not a function ↓

cause Using default import instead of namespace import in ESM

fix

Replace 'import eslintScope from "eslint-scope"' with 'import * as eslintScope from "eslint-scope"'.

error Cannot find module 'eslint-scope' ↓

cause Package not installed or wrong import path when using CommonJS with .mjs extension

fix

Ensure 'eslint-scope' is listed in package.json dependencies and run npm install. For .mjs files, use ESM import syntax.

error TypeError: scopeManager.acquire is not a function ↓

cause Calling acquire on a Scope object instead of ScopeManager

fix

Use scopeManager.acquire(node), not scope.acquire(node).

error Error: The 'sourceType' option must be "script" or "module" ↓

cause Providing an invalid sourceType value

fix

Set sourceType to either "script" or "module" (e.g., sourceType: "module").

Warnings

breaking Requires Node.js ^20.19.0 || ^22.13.0 || >=24 as of v9.0.0 ↓

fix Update Node.js to a supported version (20.19.0+, 22.13.0+, or 24+).

breaking Default export removed; use namespace import (ESM) or require (CJS) ↓

fix Change 'import eslintScope from "eslint-scope"' to 'import * as eslintScope from "eslint-scope"'.

gotcha ScopeManager.acquire() may return null for nodes that do not introduce a scope ↓

fix Always check that the return value is not null before using it.

deprecated The 'optimistic' option is experimental and may be removed in future versions ↓

fix Avoid relying on optimistic scope analysis; use default behavior.

gotcha ECMAScript version must match the parser's ecmaVersion; mismatches may cause incorrect scope analysis ↓

fix Provide the same ecmaVersion to both the parser and eslint-scope.analyze().

Install

npm install eslint-scope

yarn add eslint-scope

pnpm add eslint-scope

Imports

eslintScope

wrong

import eslintScope from 'eslint-scope'

correct

import * as eslintScope from 'eslint-scope'

ESM uses namespace import; default import does not exist.

eslintScope
wrong
```
const { analyze } = require('eslint-scope')
```
correct
```
const eslintScope = require('eslint-scope')
```
CommonJS requires the full module; destructuring works but namespace import is preferred in ESM.

ScopeManager

wrong

import { ScopeManager } from 'eslint-scope'

correct

import type { ScopeManager } from 'eslint-scope'

ScopeManager is a type, not a value; use type import in TypeScript.

Scope

wrong

const { Scope } = require('eslint-scope')

correct

import type { Scope } from 'eslint-scope'

Scope is an interface; cannot be required as a value.

Quickstart

Parses JavaScript code with espree, analyzes scopes with eslint-scope, and logs global and function scope variables.

import * as eslintScope from 'eslint-scope';
import * as espree from 'espree';

const code = `const x = 1; function foo() { var y = 2; }`;
const ast = espree.parse(code, { ecmaVersion: 2022, sourceType: 'script' });
const scopeManager = eslintScope.analyze(ast, { ecmaVersion: 2022 });

console.log(scopeManager.scopes.length); // 2
console.log(scopeManager.globalScope.variables.map(v => v.name)); // ['x', 'foo']

const functionScope = scopeManager.acquire(ast.body[1]);
console.log(functionScope.variables.map(v => v.name)); // ['y']