pkce-challenge 5.0.1: generateChallenge, pkceChallenge, verifyChallenge

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/pkce-challenge@5.0.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/pkce-challenge@5.0.1
Demonstrate these symbols/APIs:
  - generateChallenge
  - pkceChallenge
  - verifyChallenge

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:sha256:7b2c65955e86c038f7e346da241ac82eefbab2b5673ced8c5f1969895d143107","contract":["pkceChallenge generates a code_verifier with default length 43 and corresponding code_challenge","pkceChallenge generates a code_verifier with specified custom length between 43 and 128","pkceChallenge throws an error when given length is outside 43 to 128","generateChallenge computes the matching base64url sha256 challenge for a given code_verifier","verifyChallenge returns true for matching verifier and challenge, and false for non-matching challenge"],"goal":"verify pkg:npm/pkce-challenge@5.0.1","kind":"HOW","packages":["pkg:npm/pkce-challenge@5.0.1"],"schemaVersion":1,"symbols":["generateChallenge","pkceChallenge","verifyChallenge"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"esm","os":"linux","osVersionBucket":"24","packageManager":"npm","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/pkce-challenge@5.0.1"],"schemaVersion":1,"subject":"pkg:npm/pkce-challenge@5.0.1","symbols":["generateChallenge","pkceChallenge","verifyChallenge"],"verifierAdapter":"node-typescript@1"}

import pkceChallenge, { generateChallenge, verifyChallenge } from "pkce-challenge";

export { pkceChallenge, generateChallenge, verifyChallenge };
export default pkceChallenge;

{
  "name": "sample-pkce-challenge",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-pkce-challenge",
      "version": "1.0.0",
      "dependencies": {
        "pkce-challenge": "5.0.1"
      }
    },
    "node_modules/pkce-challenge": {
      "version": "5.0.1",
      "resolved": "https://registry.npmjs.org/pkce-challenge/-/pkce-challenge-5.0.1.tgz",
      "integrity": "sha512-wQ0b/W4Fr01qtpHlqSqspcj3EhBvimsdh0KlHhH8HRZnMsEa0ea2fTULOXOS9ccQr3om+GcGRk4e+isrZWV8qQ==",
      "license": "MIT",
      "engines": {
        "node": ">=16.20.0"
      }
    }
  }
}

{
  "name": "sample-pkce-challenge",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "description": "Clean-room code sample for pkce-challenge@5.0.1",
  "main": "index.js",
  "dependencies": {
    "pkce-challenge": "5.0.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/pkce-challenge@5.0.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/pkce-challenge@5.0.1"
  ],
  "symbols": [
    "generateChallenge",
    "pkceChallenge",
    "verifyChallenge"
  ]
}

import assert from "node:assert/strict";
import pkceChallenge, { generateChallenge, verifyChallenge } from "pkce-challenge";

async function run() {
  // 1. pkceChallenge generates a code_verifier with default length 43 and corresponding code_challenge
  const defaultPair = await pkceChallenge();
  assert.equal(typeof defaultPair.code_verifier, "string");
  assert.equal(defaultPair.code_verifier.length, 43);
  assert.equal(typeof defaultPair.code_challenge, "string");
  assert.ok(defaultPair.code_challenge.length > 0);

  // 2. pkceChallenge generates a code_verifier with specified custom length between 43 and 128
  const customPair = await pkceChallenge(128);
  assert.equal(typeof customPair.code_verifier, "string");
  assert.equal(customPair.code_verifier.length, 128);
  assert.equal(typeof customPair.code_challenge, "string");
  assert.ok(customPair.code_challenge.length > 0);

  // 3. pkceChallenge throws an error when given length is outside 43 to 128
  await assert.rejects(
    async () => {
      await pkceChallenge(42);
    },
    (err) => {
      return typeof err === "string" && err.includes("Expected a length between 43 and 128");
    }
  );

  // 4. generateChallenge computes the matching base64url sha256 challenge for a given code_verifier
  const derivedChallenge = await generateChallenge(defaultPair.code_verifier);
  assert.equal(derivedChallenge, defaultPair.code_challenge);

  // 5. verifyChallenge returns true for matching verifier and challenge, and false for non-matching challenge
  const valid = await verifyChallenge(defaultPair.code_verifier, defaultPair.code_challenge);
  assert.equal(valid, true);

  const invalid = await verifyChallenge(defaultPair.code_verifier, "mismatched-challenge");
  assert.equal(invalid, false);

  console.log("All contract checks passed.");
}

await run();