199 lines
11 KiB
Markdown
199 lines
11 KiB
Markdown
[](https://www.npmjs.com/package/eslint-scope)
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[](https://www.npmjs.com/package/eslint-scope)
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[](https://github.com/eslint/js/actions)
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# ESLint Scope
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ESLint Scope is the [ECMAScript](http://www.ecma-international.org/publications/standards/Ecma-262.htm) scope analyzer used in ESLint. It is a fork of [escope](http://github.com/estools/escope).
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## Install
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```
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npm i eslint-scope --save
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```
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## 📖 Usage
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To use in an ESM file:
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```js
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import * as eslintScope from 'eslint-scope';
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```
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To use in a CommonJS file:
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```js
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const eslintScope = require('eslint-scope');
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```
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In order to analyze scope, you'll need to have an [ESTree](https://github.com/estree/estree) compliant AST structure to run it on. The primary method is `eslintScope.analyze()`, which takes two arguments:
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1. `ast` - the ESTree-compliant AST structure to analyze.
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2. `options` (optional) - Options to adjust how the scope is analyzed, including:
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* `ignoreEval` (default: `false`) - Set to `true` to ignore all `eval()` calls (which would normally create scopes).
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* `nodejsScope` (default: `false`) - Set to `true` to create a top-level function scope needed for CommonJS evaluation.
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* `impliedStrict` (default: `false`) - Set to `true` to evaluate the code in strict mode even outside of modules and without `"use strict"`.
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* `ecmaVersion` (default: `5`) - The version of ECMAScript to use to evaluate the code.
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* `sourceType` (default: `"script"`) - The type of JavaScript file to evaluate. Change to `"module"` for ECMAScript module code.
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* `childVisitorKeys` (default: `null`) - An object with visitor key information (like [`eslint-visitor-keys`](https://github.com/eslint/js/tree/main/packages/eslint-visitor-keys)). Without this, `eslint-scope` finds child nodes to visit algorithmically. Providing this option is a performance enhancement.
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* `fallback` (default: `"iteration"`) - The strategy to use when `childVisitorKeys` is not specified. May be a function.
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* `jsx` (default: `false`) - Enables the tracking of JSX components as variable references.
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Example:
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```js
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import * as eslintScope from 'eslint-scope';
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import * as espree from 'espree';
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import estraverse from 'estraverse';
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const options = {
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ecmaVersion: 2022,
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sourceType: "module"
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};
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const ast = espree.parse(code, { range: true, ...options });
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const scopeManager = eslintScope.analyze(ast, options);
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const currentScope = scopeManager.acquire(ast); // global scope
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estraverse.traverse(ast, {
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enter (node, parent) {
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// do stuff
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if (/Function/.test(node.type)) {
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currentScope = scopeManager.acquire(node); // get current function scope
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}
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},
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leave(node, parent) {
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if (/Function/.test(node.type)) {
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currentScope = currentScope.upper; // set to parent scope
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}
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// do stuff
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}
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});
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```
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## API
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The following section describes the API for this package. You can also read [the docs](https://eslint.org/docs/latest/extend/scope-manager-interface).
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### ScopeManager
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The `ScopeManager` class is at the core of eslint-scope and is returned when you call `eslintScope.analyze()`. It manages all scopes in a given AST.
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#### Properties
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- `scopes` - An array of all scopes.
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- `globalScope` - Reference to the global scope.
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#### Methods
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- **`acquire(node, inner)`**
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Acquires the appropriate scope for a given node.
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- `node` - The AST node to acquire the scope from.
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- `inner` - Optional boolean. When `true`, returns the innermost scope, otherwise returns the outermost scope. Default is `false`.
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- Returns: The acquired scope or `null` if no scope is found.
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- **`acquireAll(node)`**
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Acquires all scopes for a given node.
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- `node` - The AST node to acquire scopes from.
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- Returns: An array of scopes or `undefined` if none are found.
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- **`release(node, inner)`**
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Returns the upper scope for a given node.
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- `node` - The AST node to release.
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- `inner` - Optional boolean. When `true`, returns the innermost upper scope, otherwise returns the outermost upper scope. Default is `false`.
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- Returns: The upper scope or `null` if no upper scope exists.
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- **`getDeclaredVariables(node)`**
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Get variables that are declared by the node.
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- `node` - The AST node to get declarations from.
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- Returns: An array of variable objects declared by the node. If the node doesn't declare any variables, it returns an empty array.
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- **`isGlobalReturn()`**
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Determines if the global return statement should be allowed.
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- Returns: `true` if the global return is enabled.
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- **`isModule()`**
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Checks if the code should be handled as an ECMAScript module.
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- Returns: `true` if the sourceType is "module".
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- **`isImpliedStrict()`**
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Checks if implied strict mode is enabled.
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- Returns: `true` if implied strict mode is enabled.
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- **`isStrictModeSupported()`**
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Checks if strict mode is supported based on ECMAScript version.
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- Returns: `true` if the ECMAScript version supports strict mode.
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### Scope Objects
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Scopes returned by the ScopeManager methods have the following properties:
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- `type` - The type of scope (e.g., "function", "block", "global").
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- `variables` - Array of variables declared in this scope.
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- `set` - A Map of variable names to Variable objects for variables declared in this scope.
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- `references` - Array of references in this scope.
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- `through` - Array of references in this scope and its child scopes that aren't resolved in this scope or its child scopes.
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- `variableScope` - Reference to the closest variable scope.
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- `upper` - Reference to the parent scope.
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- `childScopes` - Array of child scopes.
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- `block` - The AST node that created this scope.
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### GlobalScope
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The `GlobalScope` class is a specialized scope representing the global execution context. It extends the base `Scope` class with additional functionality for handling implicitly defined global variables.
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#### Properties
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- **`implicit`** - Tracks implicitly defined global variables (those used without declaration).
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- `set` - A Map of variable names to Variable objects for implicitly defined globals.
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- `variables` - Array of implicit global Variable objects.
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- `left` - Array of References that need to be linked to the variable they refer to.
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### Variable Objects
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Each variable object has the following properties:
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- `name` - The variable name.
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- `identifiers` - Array of identifier nodes declaring this variable.
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- `references` - Array of references to this variable.
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- `defs` - Array of definition objects for this variable.
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- `scope` - The scope object where this variable is defined.
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## Contributing
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Issues and pull requests will be triaged and responded to as quickly as possible. We operate under the [ESLint Contributor Guidelines](http://eslint.org/docs/developer-guide/contributing), so please be sure to read them before contributing. If you're not sure where to dig in, check out the [issues](https://github.com/eslint/js/issues).
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## Security Policy
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We work hard to ensure that ESLint Scope is safe for everyone and that security issues are addressed quickly and responsibly. Read the full [security policy](https://github.com/eslint/.github/blob/master/SECURITY.md).
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## Build Commands
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* `npm test` - run all linting and tests
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* `npm run lint` - run all linting
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## License
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ESLint Scope is licensed under a permissive BSD 2-clause license.
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<!-- NOTE: This section is autogenerated. Do not manually edit.-->
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<!--sponsorsstart-->
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## Sponsors
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The following companies, organizations, and individuals support ESLint's ongoing maintenance and development. [Become a Sponsor](https://eslint.org/donate)
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to get your logo on our READMEs and [website](https://eslint.org/sponsors).
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<h3>Diamond Sponsors</h3>
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<p><a href="https://www.ag-grid.com/"><img src="https://images.opencollective.com/ag-grid/bec0580/logo.png" alt="AG Grid" height="128"></a></p><h3>Platinum Sponsors</h3>
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<p><a href="https://automattic.com"><img src="https://images.opencollective.com/automattic/d0ef3e1/logo.png" alt="Automattic" height="128"></a> <a href="https://www.airbnb.com/"><img src="https://images.opencollective.com/airbnb/d327d66/logo.png" alt="Airbnb" height="128"></a></p><h3>Gold Sponsors</h3>
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<p><a href="https://qlty.sh/"><img src="https://images.opencollective.com/qltysh/33d157d/logo.png" alt="Qlty Software" height="96"></a> <a href="https://trunk.io/"><img src="https://images.opencollective.com/trunkio/fb92d60/avatar.png" alt="trunk.io" height="96"></a> <a href="https://shopify.engineering/"><img src="https://avatars.githubusercontent.com/u/8085" alt="Shopify" height="96"></a></p><h3>Silver Sponsors</h3>
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<p><a href="https://vite.dev/"><img src="https://images.opencollective.com/vite/e6d15e1/logo.png" alt="Vite" height="64"></a> <a href="https://liftoff.io/"><img src="https://images.opencollective.com/liftoff/5c4fa84/logo.png" alt="Liftoff" height="64"></a> <a href="https://americanexpress.io"><img src="https://avatars.githubusercontent.com/u/3853301" alt="American Express" height="64"></a> <a href="https://stackblitz.com"><img src="https://avatars.githubusercontent.com/u/28635252" alt="StackBlitz" height="64"></a></p><h3>Bronze Sponsors</h3>
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<p><a href="https://sentry.io"><img src="https://github.com/getsentry.png" alt="Sentry" height="32"></a> <a href="https://syntax.fm"><img src="https://github.com/syntaxfm.png" alt="Syntax" height="32"></a> <a href="https://cybozu.co.jp/"><img src="https://images.opencollective.com/cybozu/933e46d/logo.png" alt="Cybozu" height="32"></a> <a href="https://www.crosswordsolver.org/anagram-solver/"><img src="https://images.opencollective.com/anagram-solver/2666271/logo.png" alt="Anagram Solver" height="32"></a> <a href="https://icons8.com/"><img src="https://images.opencollective.com/icons8/7fa1641/logo.png" alt="Icons8" height="32"></a> <a href="https://discord.com"><img src="https://images.opencollective.com/discordapp/f9645d9/logo.png" alt="Discord" height="32"></a> <a href="https://www.gitbook.com"><img src="https://avatars.githubusercontent.com/u/7111340" alt="GitBook" height="32"></a> <a href="https://nolebase.ayaka.io"><img src="https://avatars.githubusercontent.com/u/11081491" alt="Neko" height="32"></a> <a href="https://nx.dev"><img src="https://avatars.githubusercontent.com/u/23692104" alt="Nx" height="32"></a> <a href="https://opensource.mercedes-benz.com/"><img src="https://avatars.githubusercontent.com/u/34240465" alt="Mercedes-Benz Group" height="32"></a> <a href="https://herocoders.com"><img src="https://avatars.githubusercontent.com/u/37549774" alt="HeroCoders" height="32"></a> <a href="https://www.lambdatest.com"><img src="https://avatars.githubusercontent.com/u/171592363" alt="LambdaTest" height="32"></a></p>
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<h3>Technology Sponsors</h3>
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Technology sponsors allow us to use their products and services for free as part of a contribution to the open source ecosystem and our work.
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<p><a href="https://netlify.com"><img src="https://raw.githubusercontent.com/eslint/eslint.org/main/src/assets/images/techsponsors/netlify-icon.svg" alt="Netlify" height="32"></a> <a href="https://algolia.com"><img src="https://raw.githubusercontent.com/eslint/eslint.org/main/src/assets/images/techsponsors/algolia-icon.svg" alt="Algolia" height="32"></a> <a href="https://1password.com"><img src="https://raw.githubusercontent.com/eslint/eslint.org/main/src/assets/images/techsponsors/1password-icon.svg" alt="1Password" height="32"></a></p>
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