@typescript-eslint/scope-manager 8.65.0: CatchScope

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 @typescript-eslint/scope-manager.CatchScope in pkg:npm/%40typescript-eslint/scope-manager@8.65.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40typescript-eslint/scope-manager@8.65.0
Demonstrate these symbols/APIs:
  - @typescript-eslint/scope-manager.CatchScope

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.

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        "@typescript-eslint/visitor-keys": "8.65.0"
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{
  "name": "verify-scope-manager-catch-scope",
  "version": "1.0.0",
  "private": true,
  "description": "verify @typescript-eslint/scope-manager.CatchScope in pkg:npm/@typescript-eslint/scope-manager@8.65.0",
  "main": "src/index.js",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "@typescript-eslint/scope-manager": "8.65.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify @typescript-eslint/scope-manager.CatchScope in pkg:npm/%40typescript-eslint/scope-manager@8.65.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40typescript-eslint/scope-manager@8.65.0"
  ],
  "symbols": [
    "@typescript-eslint/scope-manager.CatchScope"
  ]
}

const { ScopeManager, CatchScope, analyze } = require('@typescript-eslint/scope-manager');

/**
 * Creates an instance of CatchScope directly given a ScopeManager, upper scope, and CatchClause node.
 *
 * @param {ScopeManager} scopeManager - The managing ScopeManager instance
 * @param {import('@typescript-eslint/scope-manager').Scope} upperScope - The parent scope
 * @param {object} catchNode - The ESTree/TSESTree CatchClause AST node
 * @returns {CatchScope} The newly instantiated CatchScope
 */
function createCatchScope(scopeManager, upperScope, catchNode) {
  return new CatchScope(scopeManager, upperScope, catchNode);
}

/**
 * Nests a CatchScope within an existing ScopeManager hierarchy for a CatchClause AST node.
 *
 * @param {ScopeManager} scopeManager - The ScopeManager instance
 * @param {object} catchNode - The ESTree/TSESTree CatchClause AST node
 * @returns {CatchScope} The nested CatchScope
 */
function nestCatchScopeInManager(scopeManager, catchNode) {
  return scopeManager.nestCatchScope(catchNode);
}

/**
 * Analyzes an ESTree/TSESTree Program AST containing a try-catch construct and returns all CatchScope instances.
 *
 * @param {object} ast - The ESTree Program AST node
 * @param {object} [options={}] - Optional analyzer options
 * @returns {CatchScope[]} Array of CatchScope instances found in the analyzed AST
 */
function findCatchScopes(ast, options = {}) {
  const scopeManager = analyze(ast, options);
  return scopeManager.scopes.filter((scope) => scope instanceof CatchScope);
}

/**
 * Extracts variable names defined within a CatchScope (e.g., error parameter bindings).
 *
 * @param {CatchScope} catchScope - The CatchScope instance
 * @returns {string[]} Array of declared variable names
 */
function getCatchVariableNames(catchScope) {
  return catchScope.variables.map((variable) => variable.name);
}

module.exports = {
  CatchScope,
  ScopeManager,
  analyze,
  createCatchScope,
  nestCatchScopeInManager,
  findCatchScopes,
  getCatchVariableNames,
};

import assert from 'node:assert/strict';
import { createRequire } from 'node:module';

const require = createRequire(import.meta.url);
const {
  CatchScope,
  ScopeManager,
  createCatchScope,
  nestCatchScopeInManager,
  findCatchScopes,
  getCatchVariableNames,
} = require('../src/index.js');
const scopeManagerModule = require('@typescript-eslint/scope-manager');

// 1. CatchScope is exported by @typescript-eslint/scope-manager and instantiates with catch ScopeType, upper scope, and block AST node
assert.strictEqual(typeof CatchScope, 'function', 'CatchScope constructor should be exported as a function');
assert.strictEqual(CatchScope, scopeManagerModule.CatchScope, 'CatchScope export must match package CatchScope export');

const sm1 = new ScopeManager({});
const globalNode1 = { type: 'Program', body: [] };
const globalScope1 = sm1.nestGlobalScope(globalNode1);
const catchNode1 = {
  type: 'CatchClause',
  param: null,
  body: { type: 'BlockStatement', body: [] },
};
const directScope = createCatchScope(sm1, globalScope1, catchNode1);

assert.strictEqual(directScope instanceof CatchScope, true, 'Instance should be an instanceof CatchScope');
assert.strictEqual(directScope.type, 'catch', 'Scope type must be "catch"');
assert.strictEqual(directScope.upper, globalScope1, 'CatchScope upper must point to the parent scope');
assert.strictEqual(directScope.block, catchNode1, 'CatchScope block must point to the CatchClause node');

// 2. ScopeManager.nestCatchScope creates and registers a CatchScope within the active scope hierarchy
const sm2 = new ScopeManager({});
const globalNode2 = { type: 'Program', body: [] };
sm2.nestGlobalScope(globalNode2);
const catchNode2 = {
  type: 'CatchClause',
  param: null,
  body: { type: 'BlockStatement', body: [] },
};

const nestedScope = nestCatchScopeInManager(sm2, catchNode2);
assert.strictEqual(nestedScope instanceof CatchScope, true, 'nestedScope should be an instance of CatchScope');
assert.strictEqual(nestedScope.type, 'catch', 'nestedScope type must be "catch"');
assert.strictEqual(sm2.scopes.includes(nestedScope), true, 'ScopeManager scopes array must contain the CatchScope');
assert.strictEqual(sm2.acquire(catchNode2), nestedScope, 'ScopeManager acquire must resolve the CatchClause to the CatchScope');
assert.strictEqual(sm2.currentScope, nestedScope, 'ScopeManager currentScope should be updated to the CatchScope');

// 3. analyze produces a CatchScope for try-catch statements with catch parameter recorded in variables and set
const astWithParam = {
  type: 'Program',
  sourceType: 'script',
  body: [
    {
      type: 'TryStatement',
      block: { type: 'BlockStatement', body: [] },
      handler: {
        type: 'CatchClause',
        param: { type: 'Identifier', name: 'err' },
        body: {
          type: 'BlockStatement',
          body: [
            {
              type: 'ExpressionStatement',
              expression: { type: 'Identifier', name: 'err' },
            },
          ],
        },
      },
      finalizer: null,
    },
  ],
};

const catchScopesWithParam = findCatchScopes(astWithParam);
assert.strictEqual(catchScopesWithParam.length, 1, 'Exactly one CatchScope should be found in AST');
const [catchScope3] = catchScopesWithParam;

assert.strictEqual(catchScope3.type, 'catch', 'Scope type must be "catch"');
assert.strictEqual(catchScope3.set.has('err'), true, 'CatchScope set must contain the error variable');
const names = getCatchVariableNames(catchScope3);
assert.deepStrictEqual(names, ['err'], 'Variables declared in CatchScope must match parameter name');

const errVariable = catchScope3.set.get('err');
assert.strictEqual(errVariable.name, 'err');
assert.strictEqual(errVariable.defs[0].type, 'CatchClause', 'Variable definition type should be CatchClause');
assert.strictEqual(errVariable.references.length, 1, 'Variable should resolve the identifier reference in catch body');
assert.strictEqual(errVariable.references[0].identifier.name, 'err');

// 4. CatchScope defines separate variables for destructured object pattern parameters
const astDestructured = {
  type: 'Program',
  sourceType: 'script',
  body: [
    {
      type: 'TryStatement',
      block: { type: 'BlockStatement', body: [] },
      handler: {
        type: 'CatchClause',
        param: {
          type: 'ObjectPattern',
          properties: [
            {
              type: 'Property',
              key: { type: 'Identifier', name: 'message' },
              value: { type: 'Identifier', name: 'message' },
              kind: 'init',
              method: false,
              shorthand: true,
              computed: false,
            },
            {
              type: 'Property',
              key: { type: 'Identifier', name: 'code' },
              value: { type: 'Identifier', name: 'code' },
              kind: 'init',
              method: false,
              shorthand: true,
              computed: false,
            },
          ],
        },
        body: {
          type: 'BlockStatement',
          body: [
            {
              type: 'ExpressionStatement',
              expression: { type: 'Identifier', name: 'message' },
            },
          ],
        },
      },
      finalizer: null,
    },
  ],
};

const [catchScope4] = findCatchScopes(astDestructured);
assert.ok(catchScope4, 'CatchScope should be found for destructured pattern');
assert.strictEqual(catchScope4.set.has('message'), true, 'Scope set should have "message" variable');
assert.strictEqual(catchScope4.set.has('code'), true, 'Scope set should have "code" variable');
const destructuredNames = getCatchVariableNames(catchScope4);
assert.strictEqual(destructuredNames.length, 2, 'Should define two variables for the two pattern properties');
assert.strictEqual(destructuredNames.includes('message'), true);
assert.strictEqual(destructuredNames.includes('code'), true);

// 5. CatchScope handles optional catch binding with null parameter and links child block scopes
const astOptional = {
  type: 'Program',
  sourceType: 'script',
  body: [
    {
      type: 'TryStatement',
      block: { type: 'BlockStatement', body: [] },
      handler: {
        type: 'CatchClause',
        param: null,
        body: {
          type: 'BlockStatement',
          body: [],
        },
      },
      finalizer: null,
    },
  ],
};

const [catchScope5] = findCatchScopes(astOptional);
assert.ok(catchScope5, 'CatchScope should be created even when param is null');
assert.strictEqual(catchScope5.variables.length, 0, 'Variables list must be empty for optional catch binding');
assert.strictEqual(catchScope5.block.param, null, 'CatchScope block param should be null');
assert.strictEqual(catchScope5.childScopes.length, 1, 'CatchScope must contain the inner body BlockScope as child');
assert.strictEqual(catchScope5.childScopes[0].type, 'block', 'Child scope should have type "block"');
assert.strictEqual(catchScope5.childScopes[0].upper, catchScope5, 'Child block scope upper pointer must link to CatchScope');

console.log('All CatchScope contract assertions passed successfully.');