es-module-lexer 1.7.0: init

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 init in pkg:npm/es-module-lexer@1.7.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/es-module-lexer@1.7.0
Demonstrate these symbols/APIs:
  - init

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:e0e6380b27e99d8ca6a84e009b257a924c13f90b5fee50b5274e31d821189443","contract":["init is exported as a Promise that resolves when the WebAssembly lexer is initialized","initializeLexer awaits init and resolves successfully","parseEsm successfully parses module imports and exports after initialization"],"goal":"verify init in pkg:npm/es-module-lexer@1.7.0","kind":"HOW","packages":["pkg:npm/es-module-lexer@1.7.0"],"schemaVersion":1,"symbols":["init"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/es-module-lexer@1.7.0"],"schemaVersion":1,"subject":"pkg:npm/es-module-lexer@1.7.0","symbols":["init"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-es-module-lexer-init",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-es-module-lexer-init",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "es-module-lexer": "1.7.0"
      }
    },
    "node_modules/es-module-lexer": {
      "version": "1.7.0",
      "resolved": "https://registry.npmjs.org/es-module-lexer/-/es-module-lexer-1.7.0.tgz",
      "integrity": "sha512-jEQoCwk8hyb2AZziIOLhDqpm5+2ww5uIE6lkO/6jcOCusfk6LhMHpXXfBLXTZ7Ydyt0j4VoUQv6uGNYbdW+kBA==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-es-module-lexer-init",
  "version": "1.0.0",
  "private": true,
  "description": "verify init in pkg:npm/es-module-lexer@1.7.0",
  "main": "src/index.js",
  "license": "MIT-0",
  "dependencies": {
    "es-module-lexer": "1.7.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify init in pkg:npm/es-module-lexer@1.7.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/es-module-lexer@1.7.0"
  ],
  "symbols": [
    "init"
  ]
}

const { init, parse } = require('es-module-lexer');

/**
 * Ensures the WebAssembly lexer is initialized before parsing.
 * @returns {Promise<void>}
 */
async function initializeLexer() {
  await init;
}

/**
 * Parses source code after ensuring the WebAssembly lexer is initialized.
 * @param {string} source - ESM source code.
 * @returns {Promise<[readonly any[], readonly any[], boolean, boolean]>}
 */
async function parseEsm(source) {
  await init;
  return parse(source);
}

module.exports = {
  init,
  initializeLexer,
  parseEsm
};

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

const require = createRequire(import.meta.url);
const { init, initializeLexer, parseEsm } = require('../src/index.js');
const esModuleLexer = require('es-module-lexer');

// 1. Verify init is exported as a Promise / Thenable
assert.ok(init, 'init must be defined');
assert.ok(init instanceof Promise || typeof init.then === 'function', 'init must be a Promise or thenable');
assert.strictEqual(init, esModuleLexer.init, 'init export must match es-module-lexer.init');

// 2. Verify initializeLexer awaits init and resolves successfully
await initializeLexer();
await init;

// 3. Verify parseEsm parses import and export declarations after initialization
const source = `
import { readFile } from 'node:fs/promises';
export const helper = true;
`;
const [imports, exports, facade, hasModuleSyntax] = await parseEsm(source);

assert.strictEqual(imports.length, 1, 'should find exactly 1 import');
assert.strictEqual(imports[0].n, 'node:fs/promises', 'imported module name should match');
assert.strictEqual(exports.length, 1, 'should find exactly 1 export');
assert.strictEqual(exports[0].n, 'helper', 'exported symbol name should match');
assert.strictEqual(hasModuleSyntax, true, 'hasModuleSyntax should be true');

console.log('Contract assertions passed.');