@eslint/plugin-kit 0.7.3: TextSourceCodeBase.getAncestors

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify TextSourceCodeBase.getAncestors in pkg:npm/%40eslint/plugin-kit@0.7.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40eslint/plugin-kit@0.7.3
Demonstrate these symbols/APIs:
  - TextSourceCodeBase.getAncestors

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:4ed5df7fc92365df518c72f1e8217b2415996f3493cf6e32248731b2ec554eee","constraints":{"executionContext":"node"},"contract":["assert TextSourceCodeBase getAncestors throws TypeError when node is missing","assert TextSourceCodeBase getAncestors throws error when getParent is not implemented","assert TextSourceCodeBase getAncestors returns empty array for root node without parent","assert TextSourceCodeBase getAncestors returns ancestors ordered from root to immediate parent","assert TreeSourceCode resolves ancestors across multiple nested AST levels"],"goal":"verify TextSourceCodeBase.getAncestors in pkg:npm/%40eslint/plugin-kit@0.7.3","kind":"HOW","packages":["pkg:npm/%40eslint/plugin-kit@0.7.3"],"schemaVersion":1,"symbols":["TextSourceCodeBase.getAncestors"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/%40eslint/plugin-kit@0.7.3"],"schemaVersion":1,"subject":"pkg:npm/%40eslint/plugin-kit@0.7.3","symbols":["TextSourceCodeBase.getAncestors"],"verifierAdapter":"node-typescript@1"}

const { TextSourceCodeBase } = require("@eslint/plugin-kit");

/**
 * TextSourceCodeBase subclass that resolves parent nodes via an internal mapping.
 */
class TreeSourceCode extends TextSourceCodeBase {
  /**
   * Internal mapping from child nodes to their parent nodes.
   * @type {Map<object, object>}
   */
  #parents = new Map();

  /**
   * @param {object} options
   * @param {string} options.text
   * @param {object} options.ast
   * @param {Array<[object, object]>} [options.parents]
   * @param {RegExp} [options.lineEndingPattern]
   */
  constructor({ text, ast, parents = [], lineEndingPattern }) {
    super({ text, ast, lineEndingPattern });
    for (const [child, parent] of parents) {
      this.#parents.set(child, parent);
    }
  }

  /**
   * Returns the parent of the given node.
   * @param {object} node
   * @returns {object|undefined}
   */
  getParent(node) {
    return this.#parents.get(node);
  }
}

module.exports = {
  TextSourceCodeBase,
  TreeSourceCode,
};

{
  "name": "sample-eslint-plugin-kit-text-source-code-base",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-eslint-plugin-kit-text-source-code-base",
      "version": "1.0.0",
      "dependencies": {
        "@eslint/plugin-kit": "0.7.3"
      },
      "license": "MIT-0"
    },
    "node_modules/@eslint/core": {
      "version": "1.2.1",
      "resolved": "https://registry.npmjs.org/@eslint/core/-/core-1.2.1.tgz",
      "integrity": "sha512-MwcE1P+AZ4C6DWlpin/OmOA54mmIZ/+xZuJiQd4SyB29oAJjN30UW9wkKNptW2ctp4cEsvhlLY/CsQ1uoHDloQ==",
      "license": "Apache-2.0",
      "dependencies": {
        "@types/json-schema": "^7.0.15"
      },
      "engines": {
        "node": "^20.19.0 || ^22.13.0 || >=24"
      }
    },
    "node_modules/@eslint/plugin-kit": {
      "version": "0.7.3",
      "resolved": "https://registry.npmjs.org/@eslint/plugin-kit/-/plugin-kit-0.7.3.tgz",
      "integrity": "sha512-IkO+/KEUvwbVpiURZg+P7zF74z5Jxe0UgJxVni+RtoHQ6IZieXaO02kmadomap/q+l6bc/jdPGGqTjhuZnuz1Q==",
      "license": "Apache-2.0",
      "dependencies": {
        "@eslint/core": "^1.2.1",
        "levn": "^0.4.1"
      },
      "engines": {
        "node": "^20.19.0 || ^22.13.0 || >=24"
      }
    },
    "node_modules/@types/json-schema": {
      "version": "7.0.15",
      "resolved": "https://registry.npmjs.org/@types/json-schema/-/json-schema-7.0.15.tgz",
      "integrity": "sha512-5+fP8P8MFNC+AyZCDxrB2pkZFPGzqQWUzpSeuuVLvm8VMcorNYavBqoFcxK8bQz4Qsbn4oUEEem4wDLfcysGHA==",
      "license": "MIT"
    },
    "node_modules/levn": {
      "version": "0.4.1",
      "resolved": "https://registry.npmjs.org/levn/-/levn-0.4.1.tgz",
      "integrity": "sha512-+bT2uH4E5LGE7h/n3evcS/sQlJXCpIp6ym8OWJ5eV6+67Dsql/LaaT7qJBAt2rzfoa/5QBGBhxDix1dMt2kQKQ==",
      "license": "MIT",
      "dependencies": {
        "prelude-ls": "^1.2.1",
        "type-check": "~0.4.0"
      },
      "engines": {
        "node": ">= 0.8.0"
      }
    },
    "node_modules/prelude-ls": {
      "version": "1.2.1",
      "resolved": "https://registry.npmjs.org/prelude-ls/-/prelude-ls-1.2.1.tgz",
      "integrity": "sha512-vkcDPrRZo1QZLbn5RLGPpg/WmIQ65qoWWhcGKf/b5eplkkarX0m9z8ppCat4mlOqUsWpyNuYgO3VRyrYHSzX5g==",
      "license": "MIT",
      "engines": {
        "node": ">= 0.8.0"
      }
    },
    "node_modules/type-check": {
      "version": "0.4.0",
      "resolved": "https://registry.npmjs.org/type-check/-/type-check-0.4.0.tgz",
      "integrity": "sha512-XleUoc9uwGXqjWwXaUTZAmzMcFZ5858QA2vvx1Ur5xIcixXIP+8LnFDgRplU30us6teqdlskFfu+ae4K79Ooew==",
      "license": "MIT",
      "dependencies": {
        "prelude-ls": "^1.2.1"
      },
      "engines": {
        "node": ">= 0.8.0"
      }
    }
  }
}

{
  "name": "sample-eslint-plugin-kit-text-source-code-base",
  "version": "1.0.0",
  "description": "Clean-room sample verifying TextSourceCodeBase.getAncestors from @eslint/plugin-kit",
  "main": "index.js",
  "license": "MIT-0",
  "dependencies": {
    "@eslint/plugin-kit": "0.7.3"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify TextSourceCodeBase.getAncestors in pkg:npm/%40eslint/plugin-kit@0.7.3",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40eslint/plugin-kit@0.7.3"
  ],
  "symbols": [
    "TextSourceCodeBase.getAncestors"
  ]
}

import assert from "node:assert";
import { TextSourceCodeBase, TreeSourceCode } from "../index.js";

// Subclass without implementing getParent
class UnimplementedSourceCode extends TextSourceCodeBase {}

// 1. assert TextSourceCodeBase getAncestors throws TypeError when node is missing
{
  const ast = { type: "Program" };
  const sourceCode = new TreeSourceCode({ text: "let a = 1;", ast });
  assert.throws(
    () => sourceCode.getAncestors(),
    {
      name: "TypeError",
      message: "Missing required argument: node.",
    }
  );
  assert.throws(
    () => sourceCode.getAncestors(null),
    {
      name: "TypeError",
      message: "Missing required argument: node.",
    }
  );
}

// 2. assert TextSourceCodeBase getAncestors throws error when getParent is not implemented
{
  const ast = { type: "Program" };
  const sourceCode = new UnimplementedSourceCode({ text: "let a = 1;", ast });
  const node = { type: "Identifier", name: "a" };
  assert.throws(
    () => sourceCode.getAncestors(node),
    {
      name: "Error",
      message: "Not implemented.",
    }
  );
}

// 3. assert TextSourceCodeBase getAncestors returns empty array for root node without parent
{
  const ast = { type: "Program" };
  const sourceCode = new TreeSourceCode({ text: "let a = 1;", ast });
  const ancestors = sourceCode.getAncestors(ast);
  assert.ok(Array.isArray(ancestors));
  assert.strictEqual(ancestors.length, 0);
}

// 4. assert TextSourceCodeBase getAncestors returns ancestors ordered from root to immediate parent
{
  const root = { type: "Program" };
  const decl = { type: "VariableDeclaration" };
  const id = { type: "Identifier", name: "x" };

  const sourceCode = new TreeSourceCode({
    text: "let x = 10;",
    ast: root,
    parents: [
      [decl, root],
      [id, decl],
    ],
  });

  const ancestors = sourceCode.getAncestors(id);
  assert.deepStrictEqual(ancestors, [root, decl]);
}

// 5. assert TreeSourceCode resolves ancestors across multiple nested AST levels
{
  const root = { type: "Program" };
  const func = { type: "FunctionDeclaration" };
  const block = { type: "BlockStatement" };
  const exprStmt = { type: "ExpressionStatement" };
  const call = { type: "CallExpression" };

  const sourceCode = new TreeSourceCode({
    text: "function fn() { call(); }",
    ast: root,
    parents: [
      [func, root],
      [block, func],
      [exprStmt, block],
      [call, exprStmt],
    ],
  });

  const ancestors = sourceCode.getAncestors(call);
  assert.strictEqual(ancestors.length, 4);
  assert.strictEqual(ancestors[0], root);
  assert.strictEqual(ancestors[1], func);
  assert.strictEqual(ancestors[2], block);
  assert.strictEqual(ancestors[3], exprStmt);
}

console.log("All contract assertions passed successfully.");