callsites 3.1.0

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 pkg:npm/callsites@3.1.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/callsites@3.1.0

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:sha256:35cd7dccbf25bcf08abc0a16ae2204a04b564b1be7bb58ac33d7a09c7d49e159","contract":["callsites returns an array of CallSite objects capturing the current execution call stack","CallSite object provides getFunctionName returning caller function name","CallSite object provides getFileName, getLineNumber, and getColumnNumber for source location","callsites captures multi-frame nested invocation sequences accurately","callsites preserves and restores existing custom Error.prepareStackTrace handlers"],"goal":"verify pkg:npm/callsites@3.1.0","kind":"HOW","packages":["pkg:npm/callsites@3.1.0"],"schemaVersion":1},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"npm","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/callsites@3.1.0"],"schemaVersion":1,"subject":"pkg:npm/callsites@3.1.0","verifierAdapter":"node-typescript@1"}

{
  "name": "sample-callsites",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-callsites",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "callsites": "3.1.0"
      }
    },
    "node_modules/callsites": {
      "version": "3.1.0",
      "resolved": "https://registry.npmjs.org/callsites/-/callsites-3.1.0.tgz",
      "integrity": "sha512-P8BjAsXvZS+VIDUI11hHCQEv74YT67YUi5JJFNWIqL235sBmjX4+qx9Muvls5ivyNENctx46xQLQ3aTuE7ssaQ==",
      "license": "MIT",
      "engines": {
        "node": ">=6"
      }
    }
  }
}

{
  "name": "sample-callsites",
  "version": "1.0.0",
  "description": "Clean-room verification sample for callsites@3.1.0",
  "type": "module",
  "main": "src/index.mjs",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "callsites": "3.1.0"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/callsites@3.1.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/callsites@3.1.0"
  ]
}

import callsites from 'callsites';

/**
 * Returns the array of CallSite objects for the current execution stack.
 * @returns {Array<any>}
 */
export function getStackCallsites() {
  return callsites();
}

/**
 * Returns caller information for the function invoking this helper.
 * @returns {{ functionName: string | null, fileName: string | null, lineNumber: number | null, columnNumber: number | null }}
 */
export function getCallerInfo() {
  const sites = callsites();
  const caller = sites[1] || sites[0];
  return {
    functionName: caller.getFunctionName(),
    fileName: caller.getFileName(),
    lineNumber: caller.getLineNumber(),
    columnNumber: caller.getColumnNumber()
  };
}

export { callsites };
export default callsites;

import assert from 'node:assert/strict';
import callsites from 'callsites';
import { getStackCallsites, getCallerInfo } from '../src/index.mjs';

// 1. callsites returns an array of CallSite objects capturing the current execution call stack
function captureDirect() {
  return callsites();
}

const directSites = captureDirect();
assert.ok(Array.isArray(directSites), 'callsites() must return an array');
assert.ok(directSites.length >= 1, 'callsites() must have at least one frame');
assert.strictEqual(typeof directSites[0].getFileName, 'function', 'CallSite object must provide CallSite API methods');

const wrapperSites = getStackCallsites();
assert.ok(Array.isArray(wrapperSites), 'getStackCallsites() must return an array');
assert.ok(wrapperSites.length >= 1, 'getStackCallsites() must have at least one frame');

// 2. CallSite object provides getFunctionName returning caller function name
function testCallerFunctionName() {
  const sites = callsites();
  return sites[0].getFunctionName();
}

assert.strictEqual(testCallerFunctionName(), 'testCallerFunctionName', 'First frame functionName must match immediate caller');

function testWrapperCaller() {
  return getCallerInfo();
}

const callerInfo = testWrapperCaller();
assert.strictEqual(callerInfo.functionName, 'testWrapperCaller', 'getCallerInfo should identify calling function');

// 3. CallSite object provides getFileName, getLineNumber, and getColumnNumber for source location
function testLocationCapture() {
  const site = callsites()[0];
  return {
    fileName: site.getFileName(),
    lineNumber: site.getLineNumber(),
    columnNumber: site.getColumnNumber()
  };
}

const loc = testLocationCapture();
assert.ok(typeof loc.fileName === 'string' && loc.fileName.length > 0, 'fileName must be a non-empty string');
assert.ok(typeof loc.lineNumber === 'number' && loc.lineNumber > 0, 'lineNumber must be a positive number');
assert.ok(typeof loc.columnNumber === 'number' && loc.columnNumber > 0, 'columnNumber must be a positive number');

// 4. callsites captures multi-frame nested invocation sequences accurately
function frameAlpha() {
  return frameBeta();
}

function frameBeta() {
  return frameGamma();
}

function frameGamma() {
  return callsites();
}

const nestedFrames = frameAlpha();
assert.ok(nestedFrames.length >= 3, 'Nested call must capture multiple stack frames');
assert.strictEqual(nestedFrames[0].getFunctionName(), 'frameGamma');
assert.strictEqual(nestedFrames[1].getFunctionName(), 'frameBeta');
assert.strictEqual(nestedFrames[2].getFunctionName(), 'frameAlpha');

// 5. callsites preserves and restores existing custom Error.prepareStackTrace handlers
const dummyHandler = (_err, _stack) => 'custom-formatted-stack';
Error.prepareStackTrace = dummyHandler;

const restoredSites = callsites();
assert.ok(Array.isArray(restoredSites), 'callsites() should succeed when custom prepareStackTrace is present');
assert.strictEqual(Error.prepareStackTrace, dummyHandler, 'Error.prepareStackTrace must be restored to custom handler');

Error.prepareStackTrace = undefined;

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