typescript 7.0.2: isClassDeclaration

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.isClassDeclaration in pkg:npm/typescript@7.0.2
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/typescript@7.0.2
Demonstrate these symbols/APIs:
  - typescript.isClassDeclaration

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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{
  "name": "typescript-is-class-declaration-sample",
  "version": "1.0.0",
  "description": "verify typescript.isClassDeclaration in pkg:npm/typescript@7.0.2",
  "type": "module",
  "main": "src/index.mjs",
  "license": "MIT-0",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "typescript": "7.0.2"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify typescript.isClassDeclaration in pkg:npm/typescript@7.0.2",
  "kind": "HOW",
  "packages": [
    "pkg:npm/typescript@7.0.2"
  ],
  "symbols": [
    "typescript.isClassDeclaration"
  ]
}

import {
  isClassDeclaration as tsIsClassDeclaration,
  SyntaxKind,
  formatSyntaxKind,
} from 'typescript/unstable/ast';
import {
  createClassDeclaration,
  createIdentifier,
  createToken,
} from 'typescript/unstable/ast/factory';

/**
 * Safely determines whether a given value is a TypeScript ClassDeclaration AST node.
 * Unlike the raw tsIsClassDeclaration, this function does not throw on null, undefined, or primitives.
 *
 * @param {unknown} node
 * @returns {boolean}
 */
export function safeIsClassDeclaration(node) {
  if (!node || typeof node !== 'object' || typeof node.kind !== 'number') {
    return false;
  }
  return tsIsClassDeclaration(node);
}

/**
 * Builds a ClassDeclaration AST node with optional name and members.
 *
 * @param {string | import('typescript/unstable/ast').Identifier} [name]
 * @param {object} [options]
 * @param {Array} [options.modifiers]
 * @param {Array} [options.typeParameters]
 * @param {Array} [options.heritageClauses]
 * @param {Array} [options.members]
 * @returns {import('typescript/unstable/ast').ClassDeclaration}
 */
export function buildClassDeclaration(name, options = {}) {
  const nameNode = typeof name === 'string' ? createIdentifier(name) : name;
  const {
    modifiers = undefined,
    typeParameters = undefined,
    heritageClauses = undefined,
    members = [],
  } = options;

  return createClassDeclaration(
    modifiers,
    nameNode,
    typeParameters,
    heritageClauses,
    members
  );
}

/**
 * Inspects a ClassDeclaration node and extracts structural information.
 *
 * @param {unknown} node
 * @returns {{ kind: number, kindName: string, name: string | null, memberCount: number, isAnonymous: boolean }}
 * @throws {TypeError} if node is not a ClassDeclaration
 */
export function describeClassDeclaration(node) {
  if (!safeIsClassDeclaration(node)) {
    throw new TypeError('Expected a TypeScript ClassDeclaration AST node');
  }

  const name = node.name?._data?.text ?? (node.name?.text || null);
  const memberCount = Array.isArray(node.members) ? node.members.length : 0;

  return {
    kind: node.kind,
    kindName: formatSyntaxKind(node.kind),
    name,
    memberCount,
    isAnonymous: name === null,
  };
}

export {
  tsIsClassDeclaration as isClassDeclaration,
  SyntaxKind,
  formatSyntaxKind,
  createClassDeclaration,
  createIdentifier,
  createToken,
};

import assert from 'node:assert/strict';
import {
  isClassDeclaration,
  safeIsClassDeclaration,
  buildClassDeclaration,
  describeClassDeclaration,
  createClassDeclaration,
  createIdentifier,
  createToken,
  SyntaxKind,
  formatSyntaxKind,
} from '../src/index.mjs';
import {
  createClassExpression,
  createFunctionDeclaration,
  createPropertyDeclaration,
} from 'typescript/unstable/ast/factory';

// Contract 1: isClassDeclaration returns true for AST nodes constructed with createClassDeclaration
{
  const className = createIdentifier('UserProfile');
  const classNode = createClassDeclaration(
    undefined, // modifiers
    className, // name
    undefined, // typeParameters
    undefined, // heritageClauses
    []         // members
  );

  assert.ok(classNode, 'Class declaration node should be created');
  assert.strictEqual(isClassDeclaration(classNode), true, 'isClassDeclaration should return true for ClassDeclaration node');
  assert.strictEqual(classNode.kind, SyntaxKind.ClassDeclaration, 'Node kind should be SyntaxKind.ClassDeclaration');
  assert.strictEqual(formatSyntaxKind(classNode.kind), 'ClassDeclaration', 'formatSyntaxKind should return ClassDeclaration');
  assert.strictEqual(classNode.name?.text, 'UserProfile', 'Class name should match');

  // Anonymous class declaration (e.g. default export class)
  const anonClass = createClassDeclaration(undefined, undefined, undefined, undefined, []);
  assert.ok(anonClass, 'Anonymous class declaration should be created');
  assert.strictEqual(isClassDeclaration(anonClass), true, 'isClassDeclaration should return true for anonymous ClassDeclaration');
  assert.strictEqual(anonClass.name, undefined, 'Anonymous class name should be undefined');

  // Helper buildClassDeclaration
  const builtClass = buildClassDeclaration('OrderManager');
  assert.strictEqual(isClassDeclaration(builtClass), true, 'buildClassDeclaration should produce a valid ClassDeclaration');
  assert.strictEqual(builtClass.name?.text, 'OrderManager');
}

// Contract 2: isClassDeclaration distinguishes ClassDeclaration nodes from other AST nodes including ClassExpression and FunctionDeclaration
{
  const exprName = createIdentifier('ExprClass');
  const classExpr = createClassExpression(undefined, exprName, undefined, undefined, []);
  assert.strictEqual(isClassDeclaration(classExpr), false, 'isClassDeclaration should return false for ClassExpression');

  const fn = createFunctionDeclaration(undefined, undefined, createIdentifier('myFunction'), undefined, [], undefined, undefined);
  assert.strictEqual(isClassDeclaration(fn), false, 'isClassDeclaration should return false for FunctionDeclaration');

  const prop = createPropertyDeclaration(undefined, createIdentifier('count'), undefined, undefined, undefined);
  assert.strictEqual(isClassDeclaration(prop), false, 'isClassDeclaration should return false for PropertyDeclaration');

  const ident = createIdentifier('myVariable');
  assert.strictEqual(isClassDeclaration(ident), false, 'isClassDeclaration should return false for Identifier');

  const token = createToken(SyntaxKind.ExportKeyword);
  assert.strictEqual(isClassDeclaration(token), false, 'isClassDeclaration should return false for Modifier token');
}

// Contract 3: safeIsClassDeclaration safely identifies ClassDeclaration AST nodes without throwing on null, undefined, or non-node values
{
  const validClass = buildClassDeclaration('Service');
  assert.strictEqual(safeIsClassDeclaration(validClass), true, 'safeIsClassDeclaration should return true for valid class');

  assert.strictEqual(safeIsClassDeclaration(null), false, 'null should return false');
  assert.strictEqual(safeIsClassDeclaration(undefined), false, 'undefined should return false');
  assert.strictEqual(safeIsClassDeclaration(42), false, 'number primitive should return false');
  assert.strictEqual(safeIsClassDeclaration('class Foo {}'), false, 'string primitive should return false');
  assert.strictEqual(safeIsClassDeclaration({}), false, 'empty object should return false');
  assert.strictEqual(safeIsClassDeclaration({ kind: SyntaxKind.Identifier }), false, 'non-class AST-like object should return false');
  assert.strictEqual(safeIsClassDeclaration({ kind: SyntaxKind.ClassDeclaration }), true, 'class-declaration AST-like object should return true');
}

// Contract 4: describeClassDeclaration inspects a ClassDeclaration node to extract metadata and throws TypeError on non-ClassDeclaration nodes
{
  const prop = createPropertyDeclaration(undefined, createIdentifier('status'), undefined, undefined, undefined);
  const classWithMember = buildClassDeclaration('Account', { members: [prop] });

  const desc = describeClassDeclaration(classWithMember);
  assert.strictEqual(desc.kind, SyntaxKind.ClassDeclaration);
  assert.strictEqual(desc.kindName, 'ClassDeclaration');
  assert.strictEqual(desc.name, 'Account');
  assert.strictEqual(desc.memberCount, 1);
  assert.strictEqual(desc.isAnonymous, false);

  const anonDesc = describeClassDeclaration(buildClassDeclaration(undefined));
  assert.strictEqual(anonDesc.name, null);
  assert.strictEqual(anonDesc.isAnonymous, true);
  assert.strictEqual(anonDesc.memberCount, 0);

  assert.throws(() => describeClassDeclaration(null), { name: 'TypeError' }, 'Should throw TypeError on null');
  assert.throws(() => describeClassDeclaration(createIdentifier('notAClass')), { name: 'TypeError' }, 'Should throw TypeError on non-class node');
}

console.log('All pkg:npm/typescript@7.0.2 contracts passed successfully.');