type-fest 0.13.1: PromiseValue

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 type-fest.PromiseValue in pkg:npm/type-fest@0.13.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/type-fest@0.13.1
Demonstrate these symbols/APIs:
  - type-fest.PromiseValue

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:sha256:96250a02d95bf62c2c63485f00ebc29040f48aba031aa82f02d2b098af37b990","contract":["type-fest package.json defines package name as type-fest and version as 0.13.1 with types entry point","type-fest index declarations export PromiseValue symbol from source/promise-value","PromiseValue type definition defines generic parameters PromiseType and Otherwise defaulting to PromiseType","PromiseValue type definition resolves wrapped Promise type to its inner Value using infer Value","PromiseValue type definition falls back to Otherwise when type does not extend Promise"],"goal":"verify type-fest.PromiseValue in pkg:npm/type-fest@0.13.1","kind":"HOW","packages":["pkg:npm/type-fest@0.13.1"],"schemaVersion":1,"symbols":["type-fest.PromiseValue"]},"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/type-fest@0.13.1"],"schemaVersion":1,"subject":"pkg:npm/type-fest@0.13.1","symbols":["type-fest.PromiseValue"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-type-fest-promise-value",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-type-fest-promise-value",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "type-fest": "0.13.1"
      }
    },
    "node_modules/type-fest": {
      "version": "0.13.1",
      "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.13.1.tgz",
      "integrity": "sha512-34R7HTnG0XIJcBSn5XhDd7nNFPRcXYRZrBB2O2jdKqYODldSzBAqzsWoZYYvduky73toYS/ESqxPvkDf/F0XMg==",
      "license": "(MIT OR CC0-1.0)",
      "engines": {
        "node": ">=10"
      },
      "funding": {
        "url": "https://github.com/sponsors/sindresorhus"
      }
    }
  }
}

{
  "name": "sample-type-fest-promise-value",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "license": "MIT-0",
  "dependencies": {
    "type-fest": "0.13.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify type-fest.PromiseValue in pkg:npm/type-fest@0.13.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/type-fest@0.13.1"
  ],
  "symbols": [
    "type-fest.PromiseValue"
  ]
}

import assert from 'node:assert/strict';
import fs from 'node:fs';
import path from 'node:path';
import { createRequire } from 'node:module';

const require = createRequire(import.meta.url);

// Contract 1: type-fest package.json defines package name as type-fest and version as 0.13.1 with types entry point
{
  const pkgJson = require('type-fest/package.json');
  assert.equal(pkgJson.name, 'type-fest');
  assert.equal(pkgJson.version, '0.13.1');
  assert.equal(pkgJson.types, 'index.d.ts');
}

// Contract 2: type-fest index declarations export PromiseValue symbol from source/promise-value
{
  const pkgDir = path.dirname(require.resolve('type-fest/package.json'));
  const indexDtsPath = path.join(pkgDir, 'index.d.ts');
  assert.ok(fs.existsSync(indexDtsPath), 'index.d.ts must exist');
  const indexDtsContent = fs.readFileSync(indexDtsPath, 'utf8');
  assert.ok(
    indexDtsContent.includes("export {PromiseValue} from './source/promise-value';"),
    'PromiseValue must be exported from index.d.ts'
  );
}

// Contract 3: PromiseValue type definition defines generic parameters PromiseType and Otherwise defaulting to PromiseType
{
  const pkgDir = path.dirname(require.resolve('type-fest/package.json'));
  const promiseValueDtsPath = path.join(pkgDir, 'source', 'promise-value.d.ts');
  assert.ok(fs.existsSync(promiseValueDtsPath), 'source/promise-value.d.ts must exist');
  const promiseValueContent = fs.readFileSync(promiseValueDtsPath, 'utf8');
  assert.ok(
    promiseValueContent.includes('export type PromiseValue<PromiseType, Otherwise = PromiseType> = PromiseType extends Promise<infer Value> ? Value : Otherwise;'),
    'PromiseValue must define generic parameters PromiseType and Otherwise defaulting to PromiseType'
  );
}

// Contract 4: PromiseValue type definition resolves wrapped Promise type to its inner Value using infer Value
{
  const pkgDir = path.dirname(require.resolve('type-fest/package.json'));
  const promiseValueDtsPath = path.join(pkgDir, 'source', 'promise-value.d.ts');
  const promiseValueContent = fs.readFileSync(promiseValueDtsPath, 'utf8');
  assert.ok(
    promiseValueContent.includes('PromiseType extends Promise<infer Value> ? Value : Otherwise;'),
    'PromiseValue must resolve wrapped Promise type using infer Value'
  );
}

// Contract 5: PromiseValue type definition falls back to Otherwise when type does not extend Promise
{
  const pkgDir = path.dirname(require.resolve('type-fest/package.json'));
  const promiseValueDtsPath = path.join(pkgDir, 'source', 'promise-value.d.ts');
  const promiseValueContent = fs.readFileSync(promiseValueDtsPath, 'utf8');
  assert.ok(
    promiseValueContent.includes(': Otherwise;'),
    'PromiseValue must fall back to Otherwise when type does not extend Promise'
  );
}

console.log('All pkg:npm/type-fest@0.13.1 PromiseValue contracts passed successfully.');