es-module-lexer 2.3.1: parse

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 es-module-lexer.parse in pkg:npm/es-module-lexer@2.3.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/es-module-lexer@2.3.1
Demonstrate these symbols/APIs:
  - es-module-lexer.parse

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:sha256:31b21f456f0f3fd6f9a20faa594909543306381b70556ebcd80341589daf5c6a","contract":["parse extracts static imports, dynamic imports, and import.meta expressions with type indicators and substring boundaries","parse parses import attributes as key-value tuples on static imports","parse extracts named and default exports with export names, local names, and statement positions","parse detects facade re-export modules and distinguishes ESM from plain scripts","parse throws ParseError with character index when source contains invalid syntax"],"goal":"verify es-module-lexer.parse in pkg:npm/es-module-lexer@2.3.1","kind":"HOW","packages":["pkg:npm/es-module-lexer@2.3.1"],"schemaVersion":1,"symbols":["es-module-lexer.parse"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"esm","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@2.3.1"],"schemaVersion":1,"subject":"pkg:npm/es-module-lexer@2.3.1","symbols":["es-module-lexer.parse"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-es-module-lexer-parse",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-es-module-lexer-parse",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "es-module-lexer": "2.3.1"
      }
    },
    "node_modules/es-module-lexer": {
      "version": "2.3.1",
      "resolved": "https://registry.npmjs.org/es-module-lexer/-/es-module-lexer-2.3.1.tgz",
      "integrity": "sha512-shc1dbU90Yl/xq1QrC7QRtfcwURZuVRfPhZbDoldJ1cn1gzDvBaBWlv0eFolj5+0znnPJz5TXLxsN77X/12KTA==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-es-module-lexer-parse",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "description": "verify es-module-lexer.parse in pkg:npm/es-module-lexer@2.3.1",
  "main": "src/index.js",
  "license": "MIT-0",
  "dependencies": {
    "es-module-lexer": "2.3.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify es-module-lexer.parse in pkg:npm/es-module-lexer@2.3.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/es-module-lexer@2.3.1"
  ],
  "symbols": [
    "es-module-lexer.parse"
  ]
}

import { init, parse, ImportType } from 'es-module-lexer';

/**
 * Initializes the lexer and parses ES module source code.
 * @param {string} source - JavaScript/ESM source code to parse.
 * @param {string} [name] - Optional filename for error reporting.
 * @returns {Promise<readonly [readonly any[], readonly any[], boolean, boolean]>}
 */
export async function parseModule(source, name) {
  await init;
  return parse(source, name);
}

export { init, parse, ImportType };

import assert from 'node:assert/strict';
import { init, parse, ImportType, parseModule } from '../src/index.js';

// 1. parse extracts static imports, dynamic imports, and import.meta expressions with type indicators and substring boundaries
await init;
assert.strictEqual(typeof parse, 'function', 'parse must be a function');

const codeWithImports = `
import defaultItem, { itemA, itemB as renamedB } from 'pkg-dep';
const lazy = import('./lazy-module.js');
const metaUrl = import.meta.url;
`;

const [imports, exports, isFacade, hasSyntax] = await parseModule(codeWithImports);
assert.strictEqual(imports.length, 3, 'must detect 3 import expressions');

// static import
assert.strictEqual(imports[0].n, 'pkg-dep');
assert.strictEqual(imports[0].d, -1, 'static import d must be -1');
assert.strictEqual(imports[0].t, ImportType.Static, 'static import type must be Static');
assert.strictEqual(codeWithImports.slice(imports[0].s, imports[0].e), 'pkg-dep');

// dynamic import
assert.strictEqual(imports[1].n, './lazy-module.js');
assert.ok(imports[1].d >= 0, 'dynamic import d must be non-negative start index');
assert.strictEqual(imports[1].t, ImportType.Dynamic, 'dynamic import type must be Dynamic');

// import.meta
assert.strictEqual(imports[2].d, -2, 'import.meta d must be -2');
assert.strictEqual(imports[2].t, ImportType.ImportMeta, 'import.meta type must be ImportMeta');
assert.strictEqual(hasSyntax, true, 'module syntax must be detected');

// 2. parse parses import attributes as key-value tuples on static imports
const codeWithAttributes = `import data from './data.json' with { type: 'json' };`;
const [attrImports] = await parseModule(codeWithAttributes);
assert.strictEqual(attrImports.length, 1);
assert.strictEqual(attrImports[0].n, './data.json');
assert.ok(attrImports[0].at !== null, 'import attributes must not be null');
assert.deepStrictEqual(attrImports[0].at, [['type', 'json']]);

// 3. parse extracts named and default exports with export names, local names, and statement positions
const codeWithExports = `
export const value = 42;
export function helper() {}
const localVal = 100;
export { localVal as publicAlias };
export default class MainClass {}
`;

const [expImports, expExports] = await parseModule(codeWithExports);
assert.strictEqual(expExports.length, 4, 'must detect 4 export statements');
const exportNames = expExports.map(e => e.n);
assert.deepStrictEqual(exportNames, ['value', 'helper', 'publicAlias', 'default']);

const aliasExport = expExports.find(e => e.n === 'publicAlias');
assert.strictEqual(aliasExport.ln, 'localVal', 'local name for alias export must be localVal');
assert.strictEqual(codeWithExports.slice(aliasExport.s, aliasExport.e), 'publicAlias');
assert.strictEqual(codeWithExports.slice(aliasExport.ls, aliasExport.le), 'localVal');
assert.strictEqual(typeof aliasExport.ss, 'number', 'statement start index must be a number');

// 4. parse detects facade re-export modules and distinguishes ESM from plain scripts
const facadeCode = `export * from 'external-lib';`;
const [facImports, facExports, isFacadeModule, hasModuleSyntaxFac] = await parseModule(facadeCode);
assert.strictEqual(facImports.length, 1);
assert.strictEqual(isFacadeModule, true, 'facade re-export must have facade=true');
assert.strictEqual(hasModuleSyntaxFac, true);

const plainScript = `const x = 10; const y = 20; console.log(x + y);`;
const [plainImports, plainExports, isPlainFacade, hasPlainSyntax] = await parseModule(plainScript);
assert.strictEqual(plainImports.length, 0);
assert.strictEqual(plainExports.length, 0);
assert.strictEqual(isPlainFacade, false);
assert.strictEqual(hasPlainSyntax, false, 'plain script must have hasModuleSyntax=false');

// 5. parse throws ParseError with character index when source contains invalid syntax
assert.throws(
  () => parse('import "unterminated string literal'),
  (err) => {
    assert.strictEqual(typeof err.message, 'string');
    assert.strictEqual(typeof err.idx, 'number');
    assert.ok(err.idx > 0, 'error index must be positive');
    return true;
  }
);

console.log('All contract assertions passed.');