resolve.exports 2.0.3: resolve entry point with package.json exports field and conditions

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: resolve entry point with package.json exports field and conditions
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/resolve.exports@2.0.3
Demonstrate these symbols/APIs:
  - resolve

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:e004e904dc6c6c0e11f77f61a8b37b849668ad9fa724b362ea6725fce3b00e0d","contract":["resolve returns matched entry point for root export specifier based on default conditions","resolve matches custom export conditions when specified in options","resolve matches require condition when require option is true","resolve matches browser condition when browser option is true","resolve resolves subpath exports using exact specifier and package name prefix","resolve expands wildcard pattern subpaths in exports map","resolve resolves internal package imports specifier starting with hash","resolve throws error when requested subpath specifier is not defined in exports","resolve throws error when exports specifier has no matching conditions"],"goal":"resolve entry point with package.json exports field and conditions","kind":"HOW","packages":["pkg:npm/resolve.exports@2.0.3"],"schemaVersion":1,"symbols":["resolve"]},"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.exports@2.0.3"],"schemaVersion":1,"subject":"pkg:npm/resolve.exports@2.0.3","symbols":["resolve"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-resolve-exports",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-resolve-exports",
      "version": "1.0.0",
      "dependencies": {
        "resolve.exports": "2.0.3"
      }
    },
    "node_modules/resolve.exports": {
      "version": "2.0.3",
      "resolved": "https://registry.npmjs.org/resolve.exports/-/resolve.exports-2.0.3.tgz",
      "integrity": "sha512-OcXjMsGdhL4XnbShKpAcSqPMzQoYkYyhbEaeSko47MjRP9NfEQMhZkXL1DoFlt9LWQn4YttrdnV6X2OiyzBi+A==",
      "license": "MIT",
      "engines": {
        "node": ">=10"
      }
    }
  }
}

{
  "name": "sample-resolve-exports",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "dependencies": {
    "resolve.exports": "2.0.3"
  }
}

{
  "schemaVersion": 1,
  "goal": "resolve entry point with package.json exports field and conditions",
  "kind": "HOW",
  "packages": [
    "pkg:npm/resolve.exports@2.0.3"
  ],
  "symbols": [
    "resolve"
  ]
}

import assert from 'node:assert/strict';
import { resolve } from 'resolve.exports';

// 1. resolve returns matched entry point for root export specifier based on default conditions
{
  const pkg = {
    name: 'sample-pkg',
    exports: {
      '.': {
        import: './dist/index.mjs',
        require: './dist/index.cjs',
        default: './dist/index.js',
      },
    },
  };

  const result = resolve(pkg, '.');
  assert.deepEqual(result, ['./dist/index.mjs']);

  const resultEmpty = resolve(pkg);
  assert.deepEqual(resultEmpty, ['./dist/index.mjs']);

  const resultPkgName = resolve(pkg, 'sample-pkg');
  assert.deepEqual(resultPkgName, ['./dist/index.mjs']);
}

// 2. resolve matches custom export conditions when specified in options
{
  const pkg = {
    name: 'sample-pkg',
    exports: {
      '.': {
        worker: './dist/worker.js',
        production: './dist/prod.js',
        default: './dist/index.js',
      },
    },
  };

  const result = resolve(pkg, '.', { conditions: ['worker'] });
  assert.deepEqual(result, ['./dist/worker.js']);

  const resultProd = resolve(pkg, '.', { conditions: ['production'] });
  assert.deepEqual(resultProd, ['./dist/prod.js']);
}

// 3. resolve matches require condition when require option is true
{
  const pkg = {
    name: 'sample-pkg',
    exports: {
      '.': {
        import: './dist/index.mjs',
        require: './dist/index.cjs',
        default: './dist/index.js',
      },
    },
  };

  const result = resolve(pkg, '.', { require: true });
  assert.deepEqual(result, ['./dist/index.cjs']);
}

// 4. resolve matches browser condition when browser option is true
{
  const pkg = {
    name: 'sample-pkg',
    exports: {
      '.': {
        browser: './dist/browser.mjs',
        node: './dist/node.mjs',
        default: './dist/default.mjs',
      },
    },
  };

  const resultBrowser = resolve(pkg, '.', { browser: true });
  assert.deepEqual(resultBrowser, ['./dist/browser.mjs']);

  const resultNode = resolve(pkg, '.', { browser: false });
  assert.deepEqual(resultNode, ['./dist/node.mjs']);
}

// 5. resolve resolves subpath exports using exact specifier and package name prefix
{
  const pkg = {
    name: 'sample-pkg',
    exports: {
      './feature': './dist/feature.js',
      './utils': {
        import: './dist/utils.mjs',
        require: './dist/utils.cjs',
      },
    },
  };

  const resultSubpath = resolve(pkg, './feature');
  assert.deepEqual(resultSubpath, ['./dist/feature.js']);

  const resultPrefixed = resolve(pkg, 'sample-pkg/feature');
  assert.deepEqual(resultPrefixed, ['./dist/feature.js']);

  const resultUtils = resolve(pkg, 'sample-pkg/utils');
  assert.deepEqual(resultUtils, ['./dist/utils.mjs']);
}

// 6. resolve expands wildcard pattern subpaths in exports map
{
  const pkg = {
    name: 'sample-pkg',
    exports: {
      './components/*': './dist/components/*.js',
      './helpers/*': './dist/helpers/*.mjs',
    },
  };

  const resultBtn = resolve(pkg, './components/Button');
  assert.deepEqual(resultBtn, ['./dist/components/Button.js']);

  const resultHelper = resolve(pkg, 'sample-pkg/helpers/format');
  assert.deepEqual(resultHelper, ['./dist/helpers/format.mjs']);
}

// 7. resolve resolves internal package imports specifier starting with hash
{
  const pkg = {
    name: 'sample-pkg',
    imports: {
      '#dep': {
        import: './internal/dep.mjs',
        require: './internal/dep.cjs',
      },
      '#utils/*': './internal/utils/*.js',
    },
  };

  const resultImport = resolve(pkg, '#dep');
  assert.deepEqual(resultImport, ['./internal/dep.mjs']);

  const resultWildcardImport = resolve(pkg, '#utils/math');
  assert.deepEqual(resultWildcardImport, ['./internal/utils/math.js']);
}

// 8. resolve throws error when requested subpath specifier is not defined in exports
{
  const pkg = {
    name: 'sample-pkg',
    exports: {
      '.': './dist/index.js',
    },
  };

  assert.throws(
    () => resolve(pkg, './nonexistent'),
    /Missing "\.\/nonexistent" specifier in "sample-pkg" package/
  );
}

// 9. resolve throws error when exports specifier has no matching conditions
{
  const pkg = {
    name: 'sample-pkg',
    exports: {
      '.': {
        custom_only: './dist/custom.js',
      },
    },
  };

  assert.throws(
    () => resolve(pkg, '.', { conditions: [], unsafe: true }),
    /No known conditions for "\." specifier in "sample-pkg" package/
  );
}