pac-resolver 7.0.1: createPacResolver

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 pac-resolver.createPacResolver in pkg:npm/pac-resolver@7.0.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/pac-resolver@7.0.1
Demonstrate these symbols/APIs:
  - pac-resolver.createPacResolver
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: esm
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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": "sample-pac-resolver",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-pac-resolver",
      "version": "1.0.0",
      "dependencies": {
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        "pac-resolver": "7.0.1"
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      "license": "MIT",
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      "license": "MIT",
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        "esprima": "^4.0.1"
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      "license": "BSD-2-Clause",
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        "estraverse": "^5.2.0",
        "esutils": "^2.0.2"
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      "bin": {
        "escodegen": "bin/escodegen.js",
        "esgenerate": "bin/esgenerate.js"
      },
      "engines": {
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      "license": "BSD-2-Clause",
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    "node_modules/netmask": {
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      "license": "MIT",
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    "node_modules/pac-resolver": {
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      "resolved": "https://registry.npmjs.org/pac-resolver/-/pac-resolver-7.0.1.tgz",
      "integrity": "sha512-5NPgf87AT2STgwa2ntRMr45jTKrYBGkVU36yT0ig/n/GMAa3oPqhZfIQ2kMEimReg0+t9kZViDVZ83qfVUlckg==",
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      "license": "BSD-3-Clause",
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      "license": "0BSD"
    }
  }
}

{
  "name": "sample-pac-resolver",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "dependencies": {
    "@tootallnate/quickjs-emscripten": "^0.23.0",
    "pac-resolver": "7.0.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pac-resolver.createPacResolver in pkg:npm/pac-resolver@7.0.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/pac-resolver@7.0.1"
  ],
  "symbols": [
    "pac-resolver.createPacResolver"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "esm",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

import assert from 'node:assert/strict';
import { getQuickJS } from '@tootallnate/quickjs-emscripten';
import { createPacResolver } from 'pac-resolver';

async function runTests() {
  const qjs = await getQuickJS();

  // Test 1: createPacResolver with PAC script string and shExpMatch routing
  {
    const pacScript = `
      function FindProxyForURL(url, host) {
        if (shExpMatch(host, '*.internal.example.com')) {
          return 'PROXY proxy1.example.com:8080; DIRECT';
        }
        if (shExpMatch(host, '*.corp.example.com')) {
          return 'PROXY proxy2.example.com:3128';
        }
        return 'DIRECT';
      }
    `;

    const findProxy = createPacResolver(qjs, pacScript);
    assert.equal(typeof findProxy, 'function', 'createPacResolver should return a resolver function');

    const res1 = await findProxy('http://service.internal.example.com/api');
    assert.equal(res1, 'PROXY proxy1.example.com:8080; DIRECT');

    const res2 = await findProxy('https://app.corp.example.com/login');
    assert.equal(res2, 'PROXY proxy2.example.com:3128');

    const res3 = await findProxy('https://public.example.com/home');
    assert.equal(res3, 'DIRECT');
  }

  // Test 2: createPacResolver with Buffer input and dnsDomainIs
  {
    const pacBuffer = Buffer.from(`
      function FindProxyForURL(url, host) {
        if (dnsDomainIs(host, '.secure.example.com')) {
          return 'HTTPS secure-proxy.example.com:443';
        }
        return 'DIRECT';
      }
    `);

    const findProxy = createPacResolver(qjs, pacBuffer);
    const res = await findProxy('https://node.secure.example.com/data');
    assert.equal(res, 'HTTPS secure-proxy.example.com:443');

    const resDirect = await findProxy('https://node.other.example.com/data');
    assert.equal(resDirect, 'DIRECT');
  }

  // Test 3: URL object support and explicit host parameter
  {
    const pacScript = `
      function FindProxyForURL(url, host) {
        return 'PROXY ' + host + '.proxy:8080';
      }
    `;

    const findProxy = createPacResolver(qjs, pacScript);
    const urlObj = new URL('http://gateway.example.com/resource');
    const resUrl = await findProxy(urlObj);
    assert.equal(resUrl, 'PROXY gateway.example.com.proxy:8080');

    const resOverrideHost = await findProxy('http://ignored.example.com', 'custom.example.com');
    assert.equal(resOverrideHost, 'PROXY custom.example.com.proxy:8080');
  }

  // Test 4: Custom sandbox helpers
  {
    const pacScript = `
      function FindProxyForURL(url, host) {
        if (customCheck(host)) {
          return 'PROXY custom.example.com:8080';
        }
        return 'DIRECT';
      }
    `;

    const findProxy = createPacResolver(qjs, pacScript, {
      sandbox: {
        customCheck: (h) => h === 'special.example.com',
      },
    });

    const resSpecial = await findProxy('http://special.example.com/');
    assert.equal(resSpecial, 'PROXY custom.example.com:8080');

    const resNormal = await findProxy('http://normal.example.com/');
    assert.equal(resNormal, 'DIRECT');
  }
}

runTests().then(() => {
  console.log('All contract tests passed.');
}).catch((err) => {
  console.error('Contract test failure:', err);
  process.exit(1);
});