resolve-from 4.0.0

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/resolve-from@4.0.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/resolve-from@4.0.0

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:sha256:3817a5d8de81e46e67b5cf8f8913c25571c1d5283d5725c2e5cfb88a963f7985","contract":["resolveFrom resolves a relative file path from a specified directory","resolveFrom resolves an installed npm package from a specified directory","resolveFrom throws MODULE_NOT_FOUND error when the target module does not exist","resolveFrom throws TypeError when fromDirectory or moduleId is not a string","resolveFrom.silent returns null instead of throwing when the target module does not exist","resolveFrom.silent returns resolved absolute path when target exists","resolveModuleFrom and tryResolveModuleFrom helper functions wrap resolveFrom and resolveFrom.silent"],"goal":"verify pkg:npm/resolve-from@4.0.0","kind":"HOW","packages":["pkg:npm/resolve-from@4.0.0"],"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/resolve-from@4.0.0"],"schemaVersion":1,"subject":"pkg:npm/resolve-from@4.0.0","verifierAdapter":"node-typescript@1"}

{
  "name": "sample-resolve-from",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-resolve-from",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "resolve-from": "4.0.0"
      }
    },
    "node_modules/resolve-from": {
      "version": "4.0.0",
      "resolved": "https://registry.npmjs.org/resolve-from/-/resolve-from-4.0.0.tgz",
      "integrity": "sha512-pb/MYmXstAkysRFx8piNI1tGFNQIFA3vkE3Gq4EuA1dF6gHp/+vgZqsCGJapvy8N3Q+4o7FwvquPJcnZ7RYy4g==",
      "license": "MIT",
      "engines": {
        "node": ">=4"
      }
    }
  }
}

{
  "name": "sample-resolve-from",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room code sample for resolve-from@4.0.0",
  "main": "src/index.js",
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "resolve-from": "4.0.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/resolve-from@4.0.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/resolve-from@4.0.0"
  ]
}

import resolveFrom from 'resolve-from';

/**
 * Resolves the path of a module from a given directory.
 *
 * @param {string} fromDirectory - Directory to resolve from.
 * @param {string} moduleId - Target module ID or file path to resolve.
 * @returns {string} Absolute path to the resolved module.
 * @throws {TypeError} If fromDirectory or moduleId is not a string.
 * @throws {Error} If module cannot be resolved (code: 'MODULE_NOT_FOUND').
 */
export function resolveModuleFrom(fromDirectory, moduleId) {
  return resolveFrom(fromDirectory, moduleId);
}

/**
 * Safely resolves the path of a module from a given directory without throwing if not found.
 *
 * @param {string} fromDirectory - Directory to resolve from.
 * @param {string} moduleId - Target module ID or file path to resolve.
 * @returns {string|null} Absolute path to the resolved module, or null if resolution fails.
 */
export function tryResolveModuleFrom(fromDirectory, moduleId) {
  return resolveFrom.silent(fromDirectory, moduleId);
}

export { resolveFrom };
export default resolveFrom;

import assert from 'node:assert/strict';
import fs from 'node:fs';
import os from 'node:os';
import path from 'node:path';
import resolveFrom, {
  resolveModuleFrom,
  tryResolveModuleFrom,
} from '../src/index.mjs';

const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'csx-resolve-from-contract-'));

try {
  // Set up mock directory structure
  const subDir = path.join(tmpDir, 'sub');
  const nodeModulesDir = path.join(tmpDir, 'node_modules', 'dummy-pkg');
  fs.mkdirSync(subDir, { recursive: true });
  fs.mkdirSync(nodeModulesDir, { recursive: true });

  const targetFile = path.join(subDir, 'target.js');
  const jsonFile = path.join(subDir, 'data.json');
  const pkgIndex = path.join(nodeModulesDir, 'index.js');
  const pkgJson = path.join(nodeModulesDir, 'package.json');

  fs.writeFileSync(targetFile, 'export const val = 42;\n');
  fs.writeFileSync(jsonFile, '{"key": "value"}\n');
  fs.writeFileSync(pkgIndex, 'module.exports = { name: "dummy" };\n');
  fs.writeFileSync(pkgJson, JSON.stringify({ name: 'dummy-pkg', main: 'index.js' }));

  // 1. resolveFrom resolves a relative file path from a specified directory
  {
    const resolved = resolveFrom(tmpDir, './sub/target.js');
    assert.strictEqual(fs.realpathSync(resolved), fs.realpathSync(targetFile));

    const resolvedWithoutExt = resolveFrom(tmpDir, './sub/target');
    assert.strictEqual(fs.realpathSync(resolvedWithoutExt), fs.realpathSync(targetFile));

    const resolvedFromSub = resolveFrom(subDir, './data.json');
    assert.strictEqual(fs.realpathSync(resolvedFromSub), fs.realpathSync(jsonFile));
  }

  // 2. resolveFrom resolves an installed npm package from a specified directory
  {
    const resolvedPkg = resolveFrom(tmpDir, 'dummy-pkg');
    assert.strictEqual(fs.realpathSync(resolvedPkg), fs.realpathSync(pkgIndex));
  }

  // 3. resolveFrom throws MODULE_NOT_FOUND error when the target module does not exist
  {
    assert.throws(
      () => resolveFrom(tmpDir, './sub/missing-file.js'),
      (err) => {
        assert.strictEqual(err.code, 'MODULE_NOT_FOUND');
        assert.ok(err.message.includes('missing-file.js'));
        return true;
      }
    );

    assert.throws(
      () => resolveFrom(tmpDir, 'non-existent-package-xyz'),
      (err) => {
        assert.strictEqual(err.code, 'MODULE_NOT_FOUND');
        return true;
      }
    );
  }

  // 4. resolveFrom throws TypeError when fromDirectory or moduleId is not a string
  {
    assert.throws(
      () => resolveFrom(null, './sub/target.js'),
      {
        name: 'TypeError',
        message: 'Expected `fromDir` to be of type `string`, got `object`'
      }
    );

    assert.throws(
      () => resolveFrom(123, './sub/target.js'),
      {
        name: 'TypeError',
        message: 'Expected `fromDir` to be of type `string`, got `number`'
      }
    );

    assert.throws(
      () => resolveFrom(tmpDir, null),
      {
        name: 'TypeError',
        message: 'Expected `moduleId` to be of type `string`, got `object`'
      }
    );

    assert.throws(
      () => resolveFrom(tmpDir, 456),
      {
        name: 'TypeError',
        message: 'Expected `moduleId` to be of type `string`, got `number`'
      }
    );
  }

  // 5. resolveFrom.silent returns null instead of throwing when the target module does not exist
  {
    const resultMissingFile = resolveFrom.silent(tmpDir, './sub/missing.js');
    assert.strictEqual(resultMissingFile, null);

    const resultMissingPkg = resolveFrom.silent(tmpDir, 'missing-package-abc');
    assert.strictEqual(resultMissingPkg, null);
  }

  // 6. resolveFrom.silent returns resolved absolute path when target exists
  {
    const result = resolveFrom.silent(tmpDir, './sub/target.js');
    assert.strictEqual(fs.realpathSync(result), fs.realpathSync(targetFile));

    const resultPkg = resolveFrom.silent(tmpDir, 'dummy-pkg');
    assert.strictEqual(fs.realpathSync(resultPkg), fs.realpathSync(pkgIndex));
  }

  // 7. resolveModuleFrom and tryResolveModuleFrom helper functions wrap resolveFrom and resolveFrom.silent
  {
    const resolved = resolveModuleFrom(tmpDir, './sub/target.js');
    assert.strictEqual(fs.realpathSync(resolved), fs.realpathSync(targetFile));

    const silentResolved = tryResolveModuleFrom(tmpDir, './sub/target.js');
    assert.strictEqual(fs.realpathSync(silentResolved), fs.realpathSync(targetFile));

    const silentMissing = tryResolveModuleFrom(tmpDir, './sub/missing.js');
    assert.strictEqual(silentMissing, null);
  }

  console.log('All resolve-from contract tests passed successfully.');
} finally {
  fs.rmSync(tmpDir, { recursive: true, force: true });
}