type-fest 0.13.1: LiteralUnion

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.LiteralUnion 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.LiteralUnion

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:db07a467eb2ba9008692f23a750c08bb07f04d7292e6fc3ce496247a955233cd","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 LiteralUnion symbol","LiteralUnion type definition imports Primitive from basic declarations","LiteralUnion type definition combines LiteralType and BaseType preserving autocomplete using empty object guard","Primitive type definition defines union of JavaScript primitive types including string, number, and boolean"],"goal":"verify type-fest.LiteralUnion in pkg:npm/type-fest@0.13.1","kind":"HOW","packages":["pkg:npm/type-fest@0.13.1"],"schemaVersion":1,"symbols":["type-fest.LiteralUnion"]},"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.LiteralUnion"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-type-fest-literal-union",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-type-fest-literal-union",
      "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-literal-union",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "license": "MIT-0",
  "dependencies": {
    "type-fest": "0.13.1"
  }
}

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

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 LiteralUnion symbol
{
  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 {LiteralUnion} from './source/literal-union';"),
    'LiteralUnion must be exported from index.d.ts'
  );
}

// Contract 3: LiteralUnion type definition imports Primitive from basic declarations
{
  const pkgDir = path.dirname(require.resolve('type-fest/package.json'));
  const literalUnionDtsPath = path.join(pkgDir, 'source', 'literal-union.d.ts');
  assert.ok(fs.existsSync(literalUnionDtsPath), 'source/literal-union.d.ts must exist');
  const literalUnionDtsContent = fs.readFileSync(literalUnionDtsPath, 'utf8');
  assert.ok(
    literalUnionDtsContent.includes("import {Primitive} from './basic';"),
    'literal-union.d.ts must import Primitive from ./basic'
  );
}

// Contract 4: LiteralUnion type definition combines LiteralType and BaseType preserving autocomplete using empty object guard
{
  const pkgDir = path.dirname(require.resolve('type-fest/package.json'));
  const literalUnionDtsPath = path.join(pkgDir, 'source', 'literal-union.d.ts');
  assert.ok(fs.existsSync(literalUnionDtsPath), 'source/literal-union.d.ts must exist');
  const literalUnionDtsContent = fs.readFileSync(literalUnionDtsPath, 'utf8');
  assert.ok(
    literalUnionDtsContent.includes('export type LiteralUnion<'),
    'LiteralUnion type must be exported'
  );
  assert.ok(
    literalUnionDtsContent.includes('LiteralType extends BaseType,'),
    'LiteralUnion must constrain LiteralType extends BaseType'
  );
  assert.ok(
    literalUnionDtsContent.includes('BaseType extends Primitive'),
    'LiteralUnion must constrain BaseType extends Primitive'
  );
  assert.ok(
    literalUnionDtsContent.includes('LiteralType | (BaseType & {_?: never})'),
    'LiteralUnion must be defined as LiteralType | (BaseType & {_?: never})'
  );
}

// Contract 5: Primitive type definition defines union of JavaScript primitive types including string, number, and boolean
{
  const pkgDir = path.dirname(require.resolve('type-fest/package.json'));
  const basicDtsPath = path.join(pkgDir, 'source', 'basic.d.ts');
  assert.ok(fs.existsSync(basicDtsPath), 'source/basic.d.ts must exist');
  const basicDtsContent = fs.readFileSync(basicDtsPath, 'utf8');
  assert.ok(
    basicDtsContent.includes('export type Primitive ='),
    'Primitive type must be exported'
  );
  assert.ok(basicDtsContent.includes('| string'), 'Primitive must include string');
  assert.ok(basicDtsContent.includes('| number'), 'Primitive must include number');
  assert.ok(basicDtsContent.includes('| boolean'), 'Primitive must include boolean');
  assert.ok(basicDtsContent.includes('| symbol'), 'Primitive must include symbol');
  assert.ok(basicDtsContent.includes('| bigint'), 'Primitive must include bigint');
}

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