code:
/* eslint no-param-reassign: 0 -- stylistic choice */

import TokenTranslator from "./token-translator.js";
import { normalizeOptions } from "./options.js";

const STATE = Symbol("espree's internal state");
const ESPRIMA_FINISH_NODE = Symbol("espree's esprimaFinishNode");

/**
 * Converts an Acorn comment to a Esprima comment.
 * @param {boolean} block True if it's a block comment, false if not.
 * @param {string} text The text of the comment.
 * @param {int} start The index at which the comment starts.
 * @param {int} end The index at which the comment ends.
 * @param {Location} startLoc The location at which the comment starts.
 * @param {Location} endLoc The location at which the comment ends.
 * @param {string} code The source code being parsed.
 * @returns {Object} The comment object.
 * @private
 */
function convertAcornCommentToEsprimaComment(block, text, start, end, startLoc, endLoc, code) {
    let type;

    if (block) {
        type = "Block";
    } else if (code.slice(start, start + 2) === "#!") {
        type = "Hashbang";
    } else {
        type = "Line";
    }

    const comment = {
        type,
        value: text
    };

    if (typeof start === "number") {
        comment.start = start;
        comment.end = end;
        comment.range = [start, end];
    }

    if (typeof startLoc === "object") {
        comment.loc = {
            start: startLoc,
            end: endLoc
        };
    }

    return comment;
}

export default () => Parser => {
    const tokTypes = Object.assign({}, Parser.acorn.tokTypes);

    if (Parser.acornJsx) {
        Object.assign(tokTypes, Parser.acornJsx.tokTypes);
    }

    return class Espree extends Parser {
        constructor(opts, code) {
            if (typeof opts !== "object" || opts === null) {
                opts = {};
            }
            if (typeof code !== "string" && !(code instanceof String)) {
                code = String(code);
            }

            // save original source type in case of commonjs
            const originalSourceType = opts.sourceType;
            const options = normalizeOptions(opts);
            const ecmaFeatures = options.ecmaFeatures || {};
            const tokenTranslator =
                options.tokens === true
                    ? new TokenTranslator(tokTypes, code)
                    : null;

            /*
             * Data that is unique to Espree and is not represented internally
             * in Acorn.
             *
             * For ES2023 hashbangs, Espree will call `onComment()` during the
             * constructor, so we must define state before having access to
             * `this`.
             */
            const state = {
                originalSourceType: originalSourceType || options.sourceType,
                tokens: tokenTranslator ? [] : null,
                comments: options.comment === true ? [] : null,
                impliedStrict: ecmaFeatures.impliedStrict === true && options.ecmaVersion >= 5,
                ecmaVersion: options.ecmaVersion,
                jsxAttrValueToken: false,
                lastToken: null,
                templateElements: []
            };

            // Initialize acorn parser.
            super({

                // do not use spread, because we don't want to pass any unknown options to acorn
                ecmaVersion: options.ecmaVersion,
                sourceType: options.sourceType,
                ranges: options.ranges,
                locations: options.locations,
                allowReserved: options.allowReserved,

                // Truthy value is true for backward compatibility.
                allowReturnOutsideFunction: options.allowReturnOutsideFunction,

                // Collect tokens
                onToken(token) {
                    if (tokenTranslator) {

                        // Use `tokens`, `ecmaVersion`, and `jsxAttrValueToken` in the state.
                        tokenTranslator.onToken(token, state);
                    }
                    if (token.type !== tokTypes.eof) {
                        state.lastToken = token;
                    }
                },

                // Collect comments
                onComment(block, text, start, end, startLoc, endLoc) {
                    if (state.comments) {
                        const comment = convertAcornCommentToEsprimaComment(block, text, start, end, startLoc, endLoc, code);

                        state.comments.push(comment);
                    }
                }
            }, code);

            /*
             * We put all of this data into a symbol property as a way to avoid
             * potential naming conflicts with future versions of Acorn.
             */
            this[STATE] = state;
        }

        tokenize() {
            do {
                this.next();
            } while (this.type !== tokTypes.eof);

            // Consume the final eof token
            this.next();

            const extra = this[STATE];
            const tokens = extra.tokens;

            if (extra.comments) {
                tokens.comments = extra.comments;
            }

            return tokens;
        }

        finishNode(...args) {
            const result = super.finishNode(...args);

            return this[ESPRIMA_FINISH_NODE](result);
        }

        finishNodeAt(...args) {
            const result = super.finishNodeAt(...args);

            return this[ESPRIMA_FINISH_NODE](result);
        }

        parse() {
            const extra = this[STATE];
            const program = super.parse();

            program.sourceType = extra.originalSourceType;

            if (extra.comments) {
                program.comments = extra.comments;
            }
            if (extra.tokens) {
                program.tokens = extra.tokens;
            }

            /*
             * Adjust opening and closing position of program to match Esprima.
             * Acorn always starts programs at range 0 whereas Esprima starts at the
             * first AST node's start (the only real difference is when there's leading
             * whitespace or leading comments). Acorn also counts trailing whitespace
             * as part of the program whereas Esprima only counts up to the last token.
             */
            if (program.body.length) {
                const [firstNode] = program.body;

                if (program.range) {
                    program.range[0] = firstNode.range[0];
                }
                if (program.loc) {
                    program.loc.start = firstNode.loc.start;
                }
                program.start = firstNode.start;
            }
            if (extra.lastToken) {
                if (program.range) {
                    program.range[1] = extra.lastToken.range[1];
                }
                if (program.loc) {
                    program.loc.end = extra.lastToken.loc.end;
                }
                program.end = extra.lastToken.end;
            }

            /*
             * https://github.com/eslint/espree/issues/349
             * Ensure that template elements have correct range information.
             * This is one location where Acorn produces a different value
             * for its start and end properties vs. the values present in the
             * range property. In order to avoid confusion, we set the start
             * and end properties to the values that are present in range.
             * This is done here, instead of in finishNode(), because Acorn
             * uses the values of start and end internally while parsing, making
             * it dangerous to change those values while parsing is ongoing.
             * By waiting until the end of parsing, we can safely change these
             * values without affect any other part of the process.
             */
            this[STATE].templateElements.forEach(templateElement => {
                const startOffset = -1;
                const endOffset = templateElement.tail ? 1 : 2;

                templateElement.start += startOffset;
                templateElement.end += endOffset;

                if (templateElement.range) {
                    templateElement.range[0] += startOffset;
                    templateElement.range[1] += endOffset;
                }

                if (templateElement.loc) {
                    templateElement.loc.start.column += startOffset;
                    templateElement.loc.end.column += endOffset;
                }
            });

            return program;
        }

        parseTopLevel(node) {
            if (this[STATE].impliedStrict) {
                this.strict = true;
            }
            return super.parseTopLevel(node);
        }

        /**
         * Overwrites the default raise method to throw Esprima-style errors.
         * @param {int} pos The position of the error.
         * @param {string} message The error message.
         * @throws {SyntaxError} A syntax error.
         * @returns {void}
         */
        raise(pos, message) {
            const loc = Parser.acorn.getLineInfo(this.input, pos);
            const err = new SyntaxError(message);

            err.index = pos;
            err.lineNumber = loc.line;
            err.column = loc.column + 1; // acorn uses 0-based columns
            throw err;
        }

        /**
         * Overwrites the default raise method to throw Esprima-style errors.
         * @param {int} pos The position of the error.
         * @param {string} message The error message.
         * @throws {SyntaxError} A syntax error.
         * @returns {void}
         */
        raiseRecoverable(pos, message) {
            this.raise(pos, message);
        }

        /**
         * Overwrites the default unexpected method to throw Esprima-style errors.
         * @param {int} pos The position of the error.
         * @throws {SyntaxError} A syntax error.
         * @returns {void}
         */
        unexpected(pos) {
            let message = "Unexpected token";

            if (pos !== null && pos !== void 0) {
                this.pos = pos;

                if (this.options.locations) {
                    while (this.pos < this.lineStart) {
                        this.lineStart = this.input.lastIndexOf("\n", this.lineStart - 2) + 1;
                        --this.curLine;
                    }
                }

                this.nextToken();
            }

            if (this.end > this.start) {
                message += ` ${this.input.slice(this.start, this.end)}`;
            }

            this.raise(this.start, message);
        }

        /*
        * Esprima-FB represents JSX strings as tokens called "JSXText", but Acorn-JSX
        * uses regular tt.string without any distinction between this and regular JS
        * strings. As such, we intercept an attempt to read a JSX string and set a flag
        * on extra so that when tokens are converted, the next token will be switched
        * to JSXText via onToken.
        */
        jsx_readString(quote) { // eslint-disable-line camelcase -- required by API
            const result = super.jsx_readString(quote);

            if (this.type === tokTypes.string) {
                this[STATE].jsxAttrValueToken = true;
            }
            return result;
        }

        /**
         * Performs last-minute Esprima-specific compatibility checks and fixes.
         * @param {ASTNode} result The node to check.
         * @returns {ASTNode} The finished node.
         */
        [ESPRIMA_FINISH_NODE](result) {

            // Acorn doesn't count the opening and closing backticks as part of templates
            // so we have to adjust ranges/locations appropriately.
            if (result.type === "TemplateElement") {

                // save template element references to fix start/end later
                this[STATE].templateElements.push(result);
            }

            if (result.type.includes("Function") && !result.generator) {
                result.generator = false;
            }

            return result;
        }
    };
};


code:
/**
 * @fileoverview A collection of methods for processing Espree's options.
 * @author Kai Cataldo
 */

//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------

const SUPPORTED_VERSIONS = [
    3,
    5,
    6, // 2015
    7, // 2016
    8, // 2017
    9, // 2018
    10, // 2019
    11, // 2020
    12, // 2021
    13, // 2022
    14, // 2023
    15 // 2024
];

/**
 * Get the latest ECMAScript version supported by Espree.
 * @returns {number} The latest ECMAScript version.
 */
export function getLatestEcmaVersion() {
    return SUPPORTED_VERSIONS[SUPPORTED_VERSIONS.length - 1];
}

/**
 * Get the list of ECMAScript versions supported by Espree.
 * @returns {number[]} An array containing the supported ECMAScript versions.
 */
export function getSupportedEcmaVersions() {
    return [...SUPPORTED_VERSIONS];
}

/**
 * Normalize ECMAScript version from the initial config
 * @param {(number|"latest")} ecmaVersion ECMAScript version from the initial config
 * @throws {Error} throws an error if the ecmaVersion is invalid.
 * @returns {number} normalized ECMAScript version
 */
function normalizeEcmaVersion(ecmaVersion = 5) {

    let version = ecmaVersion === "latest" ? getLatestEcmaVersion() : ecmaVersion;

    if (typeof version !== "number") {
        throw new Error(`ecmaVersion must be a number or "latest". Received value of type ${typeof ecmaVersion} instead.`);
    }

    // Calculate ECMAScript edition number from official year version starting with
    // ES2015, which corresponds with ES6 (or a difference of 2009).
    if (version >= 2015) {
        version -= 2009;
    }

    if (!SUPPORTED_VERSIONS.includes(version)) {
        throw new Error("Invalid ecmaVersion.");
    }

    return version;
}

/**
 * Normalize sourceType from the initial config
 * @param {string} sourceType to normalize
 * @throws {Error} throw an error if sourceType is invalid
 * @returns {string} normalized sourceType
 */
function normalizeSourceType(sourceType = "script") {
    if (sourceType === "script" || sourceType === "module") {
        return sourceType;
    }

    if (sourceType === "commonjs") {
        return "script";
    }

    throw new Error("Invalid sourceType.");
}

/**
 * Normalize parserOptions
 * @param {Object} options the parser options to normalize
 * @throws {Error} throw an error if found invalid option.
 * @returns {Object} normalized options
 */
export function normalizeOptions(options) {
    const ecmaVersion = normalizeEcmaVersion(options.ecmaVersion);
    const sourceType = normalizeSourceType(options.sourceType);
    const ranges = options.range === true;
    const locations = options.loc === true;

    if (ecmaVersion !== 3 && options.allowReserved) {

        // a value of `false` is intentionally allowed here, so a shared config can overwrite it when needed
        throw new Error("`allowReserved` is only supported when ecmaVersion is 3");
    }
    if (typeof options.allowReserved !== "undefined" && typeof options.allowReserved !== "boolean") {
        throw new Error("`allowReserved`, when present, must be `true` or `false`");
    }
    const allowReserved = ecmaVersion === 3 ? (options.allowReserved || "never") : false;
    const ecmaFeatures = options.ecmaFeatures || {};
    const allowReturnOutsideFunction = options.sourceType === "commonjs" ||
        Boolean(ecmaFeatures.globalReturn);

    if (sourceType === "module" && ecmaVersion < 6) {
        throw new Error("sourceType 'module' is not supported when ecmaVersion < 2015. Consider adding `{ ecmaVersion: 2015 }` to the parser options.");
    }

    return Object.assign({}, options, {
        ecmaVersion,
        sourceType,
        ranges,
        locations,
        allowReserved,
        allowReturnOutsideFunction
    });
}

license: mit


code:
/**
 * @fileoverview Translates tokens between Acorn format and Esprima format.
 * @author Nicholas C. Zakas
 */

//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------

// none!

//------------------------------------------------------------------------------
// Private
//------------------------------------------------------------------------------

// Esprima Token Types
const Token = {
    Boolean: "Boolean",
    EOF: "<end>",
    Identifier: "Identifier",
    PrivateIdentifier: "PrivateIdentifier",
    Keyword: "Keyword",
    Null: "Null",
    Numeric: "Numeric",
    Punctuator: "Punctuator",
    String: "String",
    RegularExpression: "RegularExpression",
    Template: "Template",
    JSXIdentifier: "JSXIdentifier",
    JSXText: "JSXText"
};

/**
 * Converts part of a template into an Esprima token.
 * @param {AcornToken[]} tokens The Acorn tokens representing the template.
 * @param {string} code The source code.
 * @returns {EsprimaToken} The Esprima equivalent of the template token.
 * @private
 */
function convertTemplatePart(tokens, code) {
    const firstToken = tokens[0],
        lastTemplateToken = tokens[tokens.length - 1];

    const token = {
        type: Token.Template,
        value: code.slice(firstToken.start, lastTemplateToken.end)
    };

    if (firstToken.loc) {
        token.loc = {
            start: firstToken.loc.start,
            end: lastTemplateToken.loc.end
        };
    }

    if (firstToken.range) {
        token.start = firstToken.range[0];
        token.end = lastTemplateToken.range[1];
        token.range = [token.start, token.end];
    }

    return token;
}

/**
 * Contains logic to translate Acorn tokens into Esprima tokens.
 * @param {Object} acornTokTypes The Acorn token types.
 * @param {string} code The source code Acorn is parsing. This is necessary
 *      to correct the "value" property of some tokens.
 * @constructor
 */
function TokenTranslator(acornTokTypes, code) {

    // token types
    this._acornTokTypes = acornTokTypes;

    // token buffer for templates
    this._tokens = [];

    // track the last curly brace
    this._curlyBrace = null;

    // the source code
    this._code = code;

}

TokenTranslator.prototype = {
    constructor: TokenTranslator,

    /**
     * Translates a single Esprima token to a single Acorn token. This may be
     * inaccurate due to how templates are handled differently in Esprima and
     * Acorn, but should be accurate for all other tokens.
     * @param {AcornToken} token The Acorn token to translate.
     * @param {Object} extra Espree extra object.
     * @returns {EsprimaToken} The Esprima version of the token.
     */
    translate(token, extra) {

        const type = token.type,
            tt = this._acornTokTypes;

        if (type === tt.name) {
            token.type = Token.Identifier;

            // TODO: See if this is an Acorn bug
            if (token.value === "static") {
                token.type = Token.Keyword;
            }

            if (extra.ecmaVersion > 5 && (token.value === "yield" || token.value === "let")) {
                token.type = Token.Keyword;
            }

        } else if (type === tt.privateId) {
            token.type = Token.PrivateIdentifier;

        } else if (type === tt.semi || type === tt.comma ||
                 type === tt.parenL || type === tt.parenR ||
                 type === tt.braceL || type === tt.braceR ||
                 type === tt.dot || type === tt.bracketL ||
                 type === tt.colon || type === tt.question ||
                 type === tt.bracketR || type === tt.ellipsis ||
                 type === tt.arrow || type === tt.jsxTagStart ||
                 type === tt.incDec || type === tt.starstar ||
                 type === tt.jsxTagEnd || type === tt.prefix ||
                 type === tt.questionDot ||
                 (type.binop && !type.keyword) ||
                 type.isAssign) {

            token.type = Token.Punctuator;
            token.value = this._code.slice(token.start, token.end);
        } else if (type === tt.jsxName) {
            token.type = Token.JSXIdentifier;
        } else if (type.label === "jsxText" || type === tt.jsxAttrValueToken) {
            token.type = Token.JSXText;
        } else if (type.keyword) {
            if (type.keyword === "true" || type.keyword === "false") {
                token.type = Token.Boolean;
            } else if (type.keyword === "null") {
                token.type = Token.Null;
            } else {
                token.type = Token.Keyword;
            }
        } else if (type === tt.num) {
            token.type = Token.Numeric;
            token.value = this._code.slice(token.start, token.end);
        } else if (type === tt.string) {

            if (extra.jsxAttrValueToken) {
                extra.jsxAttrValueToken = false;
                token.type = Token.JSXText;
            } else {
                token.type = Token.String;
            }

            token.value = this._code.slice(token.start, token.end);
        } else if (type === tt.regexp) {
            token.type = Token.RegularExpression;
            const value = token.value;

            token.regex = {
                flags: value.flags,
                pattern: value.pattern
            };
            token.value = `/${value.pattern}/${value.flags}`;
        }

        return token;
    },

    /**
     * Function to call during Acorn's onToken handler.
     * @param {AcornToken} token The Acorn token.
     * @param {Object} extra The Espree extra object.
     * @returns {void}
     */
    onToken(token, extra) {

        const tt = this._acornTokTypes,
            tokens = extra.tokens,
            templateTokens = this._tokens;

        /**
         * Flushes the buffered template tokens and resets the template
         * tracking.
         * @returns {void}
         * @private
         */
        const translateTemplateTokens = () => {
            tokens.push(convertTemplatePart(this._tokens, this._code));
            this._tokens = [];
        };

        if (token.type === tt.eof) {

            // might be one last curlyBrace
            if (this._curlyBrace) {
                tokens.push(this.translate(this._curlyBrace, extra));
            }

            return;
        }

        if (token.type === tt.backQuote) {

            // if there's already a curly, it's not part of the template
            if (this._curlyBrace) {
                tokens.push(this.translate(this._curlyBrace, extra));
                this._curlyBrace = null;
            }

            templateTokens.push(token);

            // it's the end
            if (templateTokens.length > 1) {
                translateTemplateTokens();
            }

            return;
        }
        if (token.type === tt.dollarBraceL) {
            templateTokens.push(token);
            translateTemplateTokens();
            return;
        }
        if (token.type === tt.braceR) {

            // if there's already a curly, it's not part of the template
            if (this._curlyBrace) {
                tokens.push(this.translate(this._curlyBrace, extra));
            }

            // store new curly for later
            this._curlyBrace = token;
            return;
        }
        if (token.type === tt.template || token.type === tt.invalidTemplate) {
            if (this._curlyBrace) {
                templateTokens.push(this._curlyBrace);
                this._curlyBrace = null;
            }

            templateTokens.push(token);
            return;
        }

        if (this._curlyBrace) {
            tokens.push(this.translate(this._curlyBrace, extra));
            this._curlyBrace = null;
        }

        tokens.push(this.translate(token, extra));
    }
};

//------------------------------------------------------------------------------
// Public
//------------------------------------------------------------------------------

export default TokenTranslator;


code:
const version = "9.6.1";

export default version;


code:
# eslint-visitor-keys

[![npm version](https://img.shields.io/npm/v/eslint-visitor-keys.svg)](https://www.npmjs.com/package/eslint-visitor-keys)
[![Downloads/month](https://img.shields.io/npm/dm/eslint-visitor-keys.svg)](http://www.npmtrends.com/eslint-visitor-keys)
[![Build Status](https://github.com/eslint/eslint-visitor-keys/workflows/CI/badge.svg)](https://github.com/eslint/eslint-visitor-keys/actions)

Constants and utilities about visitor keys to traverse AST.

## 💿 Installation

Use [npm] to install.

```bash
$ npm install eslint-visitor-keys
```

### Requirements

- [Node.js] `^12.22.0`, `^14.17.0`, or `>=16.0.0`

## 📖 Usage

To use in an ESM file:

```js
import * as evk from "eslint-visitor-keys"
```

To use in a CommonJS file:

```js
const evk = require("eslint-visitor-keys")
```

### evk.KEYS

> type: `{ [type: string]: string[] | undefined }`

Visitor keys. This keys are frozen.

This is an object. Keys are the type of [ESTree] nodes. Their values are an array of property names which have child nodes.

For example:

```
console.log(evk.KEYS.AssignmentExpression) // → ["left", "right"]
```

### evk.getKeys(node)

> type: `(node: object) => string[]`

Get the visitor keys of a given AST node.

This is similar to `Object.keys(node)` of ES Standard, but some keys are excluded: `parent`, `leadingComments`, `trailingComments`, and names which start with `_`.

This will be used to traverse unknown nodes.

For example:

```js
const node = {
    type: "AssignmentExpression",
    left: { type: "Identifier", name: "foo" },
    right: { type: "Literal", value: 0 }
}
console.log(evk.getKeys(node)) // → ["type", "left", "right"]
```

### evk.unionWith(additionalKeys)

> type: `(additionalKeys: object) => { [type: string]: string[] | undefined }`

Make the union set with `evk.KEYS` and the given keys.

- The order of keys is, `additionalKeys` is at first, then `evk.KEYS` is concatenated after that.
- It removes duplicated keys as keeping the first one.

For example:

```js
console.log(evk.unionWith({
    MethodDefinition: ["decorators"]
})) // → { ..., MethodDefinition: ["decorators", "key", "value"], ... }
```

## 📰 Change log

See [GitHub releases](https://github.com/eslint/eslint-visitor-keys/releases).

## 🍻 Contributing

Welcome. See [ESLint contribution guidelines](https://eslint.org/docs/developer-guide/contributing/).

### Development commands

- `npm test` runs tests and measures code coverage.
- `npm run lint` checks source codes with ESLint.
- `npm run test:open-coverage` opens the code coverage report of the previous test with your default browser.

[npm]: https://www.npmjs.com/
[Node.js]: https://nodejs.org/
[ESTree]: https://github.com/estree/estree


code:
'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

/**
 * @typedef {{ readonly [type: string]: ReadonlyArray<string> }} VisitorKeys
 */

/**
 * @type {VisitorKeys}
 */
const KEYS = {
    ArrayExpression: [
        "elements"
    ],
    ArrayPattern: [
        "elements"
    ],
    ArrowFunctionExpression: [
        "params",
        "body"
    ],
    AssignmentExpression: [
        "left",
        "right"
    ],
    AssignmentPattern: [
        "left",
        "right"
    ],
    AwaitExpression: [
        "argument"
    ],
    BinaryExpression: [
        "left",
        "right"
    ],
    BlockStatement: [
        "body"
    ],
    BreakStatement: [
        "label"
    ],
    CallExpression: [
        "callee",
        "arguments"
    ],
    CatchClause: [
        "param",
        "body"
    ],
    ChainExpression: [
        "expression"
    ],
    ClassBody: [
        "body"
    ],
    ClassDeclaration: [
        "id",
        "superClass",
        "body"
    ],
    ClassExpression: [
        "id",
        "superClass",
        "body"
    ],
    ConditionalExpression: [
        "test",
        "consequent",
        "alternate"
    ],
    ContinueStatement: [
        "label"
    ],
    DebuggerStatement: [],
    DoWhileStatement: [
        "body",
        "test"
    ],
    EmptyStatement: [],
    ExperimentalRestProperty: [
        "argument"
    ],
    ExperimentalSpreadProperty: [
        "argument"
    ],
    ExportAllDeclaration: [
        "exported",
        "source"
    ],
    ExportDefaultDeclaration: [
        "declaration"
    ],
    ExportNamedDeclaration: [
        "declaration",
        "specifiers",
        "source"
    ],
    ExportSpecifier: [
        "exported",
        "local"
    ],
    ExpressionStatement: [
        "expression"
    ],
    ForInStatement: [
        "left",
        "right",
        "body"
    ],
    ForOfStatement: [
        "left",
        "right",
        "body"
    ],
    ForStatement: [
        "init",
        "test",
        "update",
        "body"
    ],
    FunctionDeclaration: [
        "id",
        "params",
        "body"
    ],
    FunctionExpression: [
        "id",
        "params",
        "body"
    ],
    Identifier: [],
    IfStatement: [
        "test",
        "consequent",
        "alternate"
    ],
    ImportDeclaration: [
        "specifiers",
        "source"
    ],
    ImportDefaultSpecifier: [
        "local"
    ],
    ImportExpression: [
        "source"
    ],
    ImportNamespaceSpecifier: [
        "local"
    ],
    ImportSpecifier: [
        "imported",
        "local"
    ],
    JSXAttribute: [
        "name",
        "value"
    ],
    JSXClosingElement: [
        "name"
    ],
    JSXClosingFragment: [],
    JSXElement: [
        "openingElement",
        "children",
        "closingElement"
    ],
    JSXEmptyExpression: [],
    JSXExpressionContainer: [
        "expression"
    ],
    JSXFragment: [
        "openingFragment",
        "children",
        "closingFragment"
    ],
    JSXIdentifier: [],
    JSXMemberExpression: [
        "object",
        "property"
    ],
    JSXNamespacedName: [
        "namespace",
        "name"
    ],
    JSXOpeningElement: [
        "name",
        "attributes"
    ],
    JSXOpeningFragment: [],
    JSXSpreadAttribute: [
        "argument"
    ],
    JSXSpreadChild: [
        "expression"
    ],
    JSXText: [],
    LabeledStatement: [
        "label",
        "body"
    ],
    Literal: [],
    LogicalExpression: [
        "left",
        "right"
    ],
    MemberExpression: [
        "object",
        "property"
    ],
    MetaProperty: [
        "meta",
        "property"
    ],
    MethodDefinition: [
        "key",
        "value"
    ],
    NewExpression: [
        "callee",
        "arguments"
    ],
    ObjectExpression: [
        "properties"
    ],
    ObjectPattern: [
        "properties"
    ],
    PrivateIdentifier: [],
    Program: [
        "body"
    ],
    Property: [
        "key",
        "value"
    ],
    PropertyDefinition: [
        "key",
        "value"
    ],
    RestElement: [
        "argument"
    ],
    ReturnStatement: [
        "argument"
    ],
    SequenceExpression: [
        "expressions"
    ],
    SpreadElement: [
        "argument"
    ],
    StaticBlock: [
        "body"
    ],
    Super: [],
    SwitchCase: [
        "test",
        "consequent"
    ],
    SwitchStatement: [
        "discriminant",
        "cases"
    ],
    TaggedTemplateExpression: [
        "tag",
        "quasi"
    ],
    TemplateElement: [],
    TemplateLiteral: [
        "quasis",
        "expressions"
    ],
    ThisExpression: [],
    ThrowStatement: [
        "argument"
    ],
    TryStatement: [
        "block",
        "handler",
        "finalizer"
    ],
    UnaryExpression: [
        "argument"
    ],
    UpdateExpression: [
        "argument"
    ],
    VariableDeclaration: [
        "declarations"
    ],
    VariableDeclarator: [
        "id",
        "init"
    ],
    WhileStatement: [
        "test",
        "body"
    ],
    WithStatement: [
        "object",
        "body"
    ],
    YieldExpression: [
        "argument"
    ]
};

// Types.
const NODE_TYPES = Object.keys(KEYS);

// Freeze the keys.
for (const type of NODE_TYPES) {
    Object.freeze(KEYS[type]);
}
Object.freeze(KEYS);

/**
 * @author Toru Nagashima <https://github.com/mysticatea>
 * See LICENSE file in root directory for full license.
 */

/**
 * @typedef {import('./visitor-keys.js').VisitorKeys} VisitorKeys
 */

// List to ignore keys.
const KEY_BLACKLIST = new Set([
    "parent",
    "leadingComments",
    "trailingComments"
]);

/**
 * Check whether a given key should be used or not.
 * @param {string} key The key to check.
 * @returns {boolean} `true` if the key should be used.
 */
function filterKey(key) {
    return !KEY_BLACKLIST.has(key) && key[0] !== "_";
}

/**
 * Get visitor keys of a given node.
 * @param {object} node The AST node to get keys.
 * @returns {readonly string[]} Visitor keys of the node.
 */
function getKeys(node) {
    return Object.keys(node).filter(filterKey);
}

// Disable valid-jsdoc rule because it reports syntax error on the type of @returns.
// eslint-disable-next-line valid-jsdoc
/**
 * Make the union set with `KEYS` and given keys.
 * @param {VisitorKeys} additionalKeys The additional keys.
 * @returns {VisitorKeys} The union set.
 */
function unionWith(additionalKeys) {
    const retv = /** @type {{
        [type: string]: ReadonlyArray<string>
    }} */ (Object.assign({}, KEYS));

    for (const type of Object.keys(additionalKeys)) {
        if (Object.prototype.hasOwnProperty.call(retv, type)) {
            const keys = new Set(additionalKeys[type]);

            for (const key of retv[type]) {
                keys.add(key);
            }

            retv[type] = Object.freeze(Array.from(keys));
        } else {
            retv[type] = Object.freeze(Array.from(additionalKeys[type]));
        }
    }

    return Object.freeze(retv);
}

exports.KEYS = KEYS;
exports.getKeys = getKeys;
exports.unionWith = unionWith;


code:
type VisitorKeys$1 = {
    readonly [type: string]: readonly string[];
};
/**
 * @typedef {{ readonly [type: string]: ReadonlyArray<string> }} VisitorKeys
 */
/**
 * @type {VisitorKeys}
 */
declare const KEYS: VisitorKeys$1;

/**
 * Get visitor keys of a given node.
 * @param {object} node The AST node to get keys.
 * @returns {readonly string[]} Visitor keys of the node.
 */
declare function getKeys(node: object): readonly string[];
/**
 * Make the union set with `KEYS` and given keys.
 * @param {VisitorKeys} additionalKeys The additional keys.
 * @returns {VisitorKeys} The union set.
 */
declare function unionWith(additionalKeys: VisitorKeys): VisitorKeys;

type VisitorKeys = VisitorKeys$1;

export { KEYS, VisitorKeys, getKeys, unionWith };


code:
/**
 * Get visitor keys of a given node.
 * @param {object} node The AST node to get keys.
 * @returns {readonly string[]} Visitor keys of the node.
 */
export function getKeys(node: object): readonly string[];
/**
 * Make the union set with `KEYS` and given keys.
 * @param {VisitorKeys} additionalKeys The additional keys.
 * @returns {VisitorKeys} The union set.
 */
export function unionWith(additionalKeys: VisitorKeys): VisitorKeys;
export { KEYS };
export type VisitorKeys = import('./visitor-keys.js').VisitorKeys;
import KEYS from "./visitor-keys.js";
//# sourceMappingURL=index.d.ts.map


code:
export default KEYS;
export type VisitorKeys = {
    readonly [type: string]: readonly string[];
};
/**
 * @typedef {{ readonly [type: string]: ReadonlyArray<string> }} VisitorKeys
 */
/**
 * @type {VisitorKeys}
 */
declare const KEYS: VisitorKeys;
//# sourceMappingURL=visitor-keys.d.ts.map


code:
/**
 * @author Toru Nagashima <https://github.com/mysticatea>
 * See LICENSE file in root directory for full license.
 */
import KEYS from "./visitor-keys.js";

/**
 * @typedef {import('./visitor-keys.js').VisitorKeys} VisitorKeys
 */

// List to ignore keys.
const KEY_BLACKLIST = new Set([
    "parent",
    "leadingComments",
    "trailingComments"
]);

/**
 * Check whether a given key should be used or not.
 * @param {string} key The key to check.
 * @returns {boolean} `true` if the key should be used.
 */
function filterKey(key) {
    return !KEY_BLACKLIST.has(key) && key[0] !== "_";
}

/**
 * Get visitor keys of a given node.
 * @param {object} node The AST node to get keys.
 * @returns {readonly string[]} Visitor keys of the node.
 */
export function getKeys(node) {
    return Object.keys(node).filter(filterKey);
}

// Disable valid-jsdoc rule because it reports syntax error on the type of @returns.
// eslint-disable-next-line valid-jsdoc
/**
 * Make the union set with `KEYS` and given keys.
 * @param {VisitorKeys} additionalKeys The additional keys.
 * @returns {VisitorKeys} The union set.
 */
export function unionWith(additionalKeys) {
    const retv = /** @type {{
        [type: string]: ReadonlyArray<string>
    }} */ (Object.assign({}, KEYS));

    for (const type of Object.keys(additionalKeys)) {
        if (Object.prototype.hasOwnProperty.call(retv, type)) {
            const keys = new Set(additionalKeys[type]);

            for (const key of retv[type]) {
                keys.add(key);
            }

            retv[type] = Object.freeze(Array.from(keys));
        } else {
            retv[type] = Object.freeze(Array.from(additionalKeys[type]));
        }
    }

    return Object.freeze(retv);
}

export { KEYS };


code:
/**
 * @typedef {{ readonly [type: string]: ReadonlyArray<string> }} VisitorKeys
 */

/**
 * @type {VisitorKeys}
 */
const KEYS = {
    ArrayExpression: [
        "elements"
    ],
    ArrayPattern: [
        "elements"
    ],
    ArrowFunctionExpression: [
        "params",
        "body"
    ],
    AssignmentExpression: [
        "left",
        "right"
    ],
    AssignmentPattern: [
        "left",
        "right"
    ],
    AwaitExpression: [
        "argument"
    ],
    BinaryExpression: [
        "left",
        "right"
    ],
    BlockStatement: [
        "body"
    ],
    BreakStatement: [
        "label"
    ],
    CallExpression: [
        "callee",
        "arguments"
    ],
    CatchClause: [
        "param",
        "body"
    ],
    ChainExpression: [
        "expression"
    ],
    ClassBody: [
        "body"
    ],
    ClassDeclaration: [
        "id",
        "superClass",
        "body"
    ],
    ClassExpression: [
        "id",
        "superClass",
        "body"
    ],
    ConditionalExpression: [
        "test",
        "consequent",
        "alternate"
    ],
    ContinueStatement: [
        "label"
    ],
    DebuggerStatement: [],
    DoWhileStatement: [
        "body",
        "test"
    ],
    EmptyStatement: [],
    ExperimentalRestProperty: [
        "argument"
    ],
    ExperimentalSpreadProperty: [
        "argument"
    ],
    ExportAllDeclaration: [
        "exported",
        "source"
    ],
    ExportDefaultDeclaration: [
        "declaration"
    ],
    ExportNamedDeclaration: [
        "declaration",
        "specifiers",
        "source"
    ],
    ExportSpecifier: [
        "exported",
        "local"
    ],
    ExpressionStatement: [
        "expression"
    ],
    ForInStatement: [
        "left",
        "right",
        "body"
    ],
    ForOfStatement: [
        "left",
        "right",
        "body"
    ],
    ForStatement: [
        "init",
        "test",
        "update",
        "body"
    ],
    FunctionDeclaration: [
        "id",
        "params",
        "body"
    ],
    FunctionExpression: [
        "id",
        "params",
        "body"
    ],
    Identifier: [],
    IfStatement: [
        "test",
        "consequent",
        "alternate"
    ],
    ImportDeclaration: [
        "specifiers",
        "source"
    ],
    ImportDefaultSpecifier: [
        "local"
    ],
    ImportExpression: [
        "source"
    ],
    ImportNamespaceSpecifier: [
        "local"
    ],
    ImportSpecifier: [
        "imported",
        "local"
    ],
    JSXAttribute: [
        "name",
        "value"
    ],
    JSXClosingElement: [
        "name"
    ],
    JSXClosingFragment: [],
    JSXElement: [
        "openingElement",
        "children",
        "closingElement"
    ],
    JSXEmptyExpression: [],
    JSXExpressionContainer: [
        "expression"
    ],
    JSXFragment: [
        "openingFragment",
        "children",
        "closingFragment"
    ],
    JSXIdentifier: [],
    JSXMemberExpression: [
        "object",
        "property"
    ],
    JSXNamespacedName: [
        "namespace",
        "name"
    ],
    JSXOpeningElement: [
        "name",
        "attributes"
    ],
    JSXOpeningFragment: [],
    JSXSpreadAttribute: [
        "argument"
    ],
    JSXSpreadChild: [
        "expression"
    ],
    JSXText: [],
    LabeledStatement: [
        "label",
        "body"
    ],
    Literal: [],
    LogicalExpression: [
        "left",
        "right"
    ],
    MemberExpression: [
        "object",
        "property"
    ],
    MetaProperty: [
        "meta",
        "property"
    ],
    MethodDefinition: [
        "key",
        "value"
    ],
    NewExpression: [
        "callee",
        "arguments"
    ],
    ObjectExpression: [
        "properties"
    ],
    ObjectPattern: [
        "properties"
    ],
    PrivateIdentifier: [],
    Program: [
        "body"
    ],
    Property: [
        "key",
        "value"
    ],
    PropertyDefinition: [
        "key",
        "value"
    ],
    RestElement: [
        "argument"
    ],
    ReturnStatement: [
        "argument"
    ],
    SequenceExpression: [
        "expressions"
    ],
    SpreadElement: [
        "argument"
    ],
    StaticBlock: [
        "body"
    ],
    Super: [],
    SwitchCase: [
        "test",
        "consequent"
    ],
    SwitchStatement: [
        "discriminant",
        "cases"
    ],
    TaggedTemplateExpression: [
        "tag",
        "quasi"
    ],
    TemplateElement: [],
    TemplateLiteral: [
        "quasis",
        "expressions"
    ],
    ThisExpression: [],
    ThrowStatement: [
        "argument"
    ],
    TryStatement: [
        "block",
        "handler",
        "finalizer"
    ],
    UnaryExpression: [
        "argument"
    ],
    UpdateExpression: [
        "argument"
    ],
    VariableDeclaration: [
        "declarations"
    ],
    VariableDeclarator: [
        "id",
        "init"
    ],
    WhileStatement: [
        "test",
        "body"
    ],
    WithStatement: [
        "object",
        "body"
    ],
    YieldExpression: [
        "argument"
    ]
};

// Types.
const NODE_TYPES = Object.keys(KEYS);

// Freeze the keys.
for (const type of NODE_TYPES) {
    Object.freeze(KEYS[type]);
}
Object.freeze(KEYS);

export default KEYS;


eslint-visitor-keys

description: Constants and utilities about visitor keys to traverse AST.

type: module

build: npm run build:cjs && npm run build:types

build:cjs: rollup -c

build:debug: npm run build:cjs -- -m && npm run build:types

build:keys: node tools/build-keys-from-ts

build:types: tsc

lint: eslint .

prepare: npm run build

release:generate:latest: eslint-generate-release

release:generate:alpha: eslint-generate-prerelease alpha

release:generate:beta: eslint-generate-prerelease beta

release:generate:rc: eslint-generate-prerelease rc

release:publish: eslint-publish-release

test: mocha tests/lib/**/*.cjs && c8 mocha tests/lib/**/*.js && npm run test:types

test:open-coverage: c8 report --reporter lcov && opener coverage/lcov-report/index.html

test:types: tsd

repository: eslint/eslint-visitor-keys


espree

description: An Esprima-compatible JavaScript parser built on Acorn

author: Nicholas C. Zakas <nicholas+npm@nczconsulting.com>

repository: eslint/espree

keywords: ast ecmascript javascript parser syntax acorn

pre-commit: lint-staged

unit: npm-run-all -s unit:*

unit:esm: c8 mocha --color --reporter progress --timeout 30000 'tests/lib/**/*.js'

unit:cjs: mocha --color --reporter progress --timeout 30000 tests/lib/commonjs.cjs

test: npm-run-all -p unit lint

lint: eslint .  --report-unused-disable-directives

fixlint: npm run lint -- --fix

build: rollup -c rollup.config.js

build:debug: npm run build -- -m

update-version: node tools/update-version.js

pretest: npm run build

prepublishOnly: npm run update-version && npm run build

sync-docs: node sync-docs.js

generate-release: eslint-generate-release

generate-alpharelease: eslint-generate-prerelease alpha

generate-betarelease: eslint-generate-prerelease beta

generate-rcrelease: eslint-generate-prerelease rc

publish-release: eslint-publish-release


code:
ESQuery is a library for querying the AST output by Esprima for patterns of syntax using a CSS style selector system. Check out the demo:

[demo](https://estools.github.io/esquery/)

The following selectors are supported:
* AST node type: `ForStatement`
* [wildcard](http://dev.w3.org/csswg/selectors4/#universal-selector): `*`
* [attribute existence](http://dev.w3.org/csswg/selectors4/#attribute-selectors): `[attr]`
* [attribute value](http://dev.w3.org/csswg/selectors4/#attribute-selectors): `[attr="foo"]` or `[attr=123]`
* attribute regex: `[attr=/foo.*/]` or (with flags) `[attr=/foo.*/is]`
* attribute conditions: `[attr!="foo"]`, `[attr>2]`, `[attr<3]`, `[attr>=2]`, or `[attr<=3]`
* nested attribute: `[attr.level2="foo"]`
* field: `FunctionDeclaration > Identifier.id`
* [First](http://dev.w3.org/csswg/selectors4/#the-first-child-pseudo) or [last](http://dev.w3.org/csswg/selectors4/#the-last-child-pseudo) child: `:first-child` or `:last-child`
* [nth-child](http://dev.w3.org/csswg/selectors4/#the-nth-child-pseudo) (no ax+b support): `:nth-child(2)`
* [nth-last-child](http://dev.w3.org/csswg/selectors4/#the-nth-last-child-pseudo) (no ax+b support): `:nth-last-child(1)`
* [descendant](http://dev.w3.org/csswg/selectors4/#descendant-combinators): `ancestor descendant`
* [child](http://dev.w3.org/csswg/selectors4/#child-combinators): `parent > child`
* [following sibling](http://dev.w3.org/csswg/selectors4/#general-sibling-combinators): `node ~ sibling`
* [adjacent sibling](http://dev.w3.org/csswg/selectors4/#adjacent-sibling-combinators): `node + adjacent`
* [negation](http://dev.w3.org/csswg/selectors4/#negation-pseudo): `:not(ForStatement)`
* [has](https://drafts.csswg.org/selectors-4/#has-pseudo): `:has(ForStatement)`
* [matches-any](http://dev.w3.org/csswg/selectors4/#matches): `:matches([attr] > :first-child, :last-child)`
* [subject indicator](http://dev.w3.org/csswg/selectors4/#subject): `!IfStatement > [name="foo"]`
* class of AST node: `:statement`, `:expression`, `:declaration`, `:function`, or `:pattern`

[![Build Status](https://travis-ci.org/estools/esquery.png?branch=master)](https://travis-ci.org/estools/esquery)