CJS Module Lexer

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

import { parse, init, initSync } from 'cjs-module-lexer';

const { parse } = require('cjs-module-lexer');

// Parse CommonJS source code
const { exports, reexports } = parse(`
  // Named exports detection
  module.exports.hello = 'world';
  exports.foo = 'bar';
  Object.defineProperty(exports, 'baz', { value: 'qux' });
  
  // Reexports detection
  module.exports = require('./other-module.js');
  
  // Literal exports assignments
  module.exports = { api: true, version: '1.0' };
`);

console.log(exports);   // ['hello', 'foo', 'baz', 'api', 'version']
console.log(reexports); // ['./other-module.js']

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

// Initialize WebAssembly (required for ESM usage)
await init();

const { exports, reexports } = parse(sourceCode);

/**
 * Parse CommonJS source code to detect exports and reexports
 * @param source - JavaScript source code to analyze
 * @param name - Optional module name for error reporting and stack traces (defaults to '@')
 * @returns Object containing detected exports and reexports arrays
 */
function parse(source: string, name?: string): Exports;

interface Exports {
  /** Array of detected named export identifiers */
  exports: string[];
  /** Array of detected reexport module specifiers */
  reexports: string[];
}

const { parse } = require('cjs-module-lexer');

// Basic named exports
const result1 = parse(`
  exports.myFunction = function() {};
  exports.myConstant = 42;
`);
// result1.exports: ['myFunction', 'myConstant']

// Object.defineProperty patterns
const result2 = parse(`
  Object.defineProperty(exports, 'computed', {
    enumerable: true,
    get: function() { return someValue; }
  });
`);
// result2.exports: ['computed']

// Module reexports
const result3 = parse(`
  if (condition) {
    module.exports = require('./dependency');
  }
`);
// result3.reexports: ['./dependency']

// Literal object assignments
const result4 = parse(`
  module.exports = {
    method1: function() {},
    method2: async function() {},
    constant: 'value'
  };
`);
// result4.exports: ['method1', 'method2', 'constant']

/**
 * Asynchronously initialize WebAssembly compilation
 * Required when using ESM imports, no-op for CommonJS
 * @returns Promise that resolves when WASM is ready
 */
function init(): Promise<void>;

/**
 * Synchronously initialize WebAssembly compilation
 * Alternative to init() for blocking compilation
 * @returns void - compilation happens synchronously
 */
function initSync(): void;

// Async initialization (recommended) - uses dist/lexer.mjs
import { parse, init } from 'cjs-module-lexer';
await init();
const result = parse(sourceCode);

// Sync initialization (blocking) - uses dist/lexer.mjs
import { parse, initSync } from 'cjs-module-lexer';
initSync();
const result = parse(sourceCode);

// CommonJS usage (no WASM, no initialization needed) - uses lexer.js
const { parse } = require('cjs-module-lexer');
const result = parse(sourceCode);

/**
 * Custom error thrown for ESM syntax in CommonJS modules
 * Extends the standard Error interface with additional properties
 */
interface ESMSyntaxError extends Error {
  /** Error code identifying this as an ESM syntax error */
  code: 'ERR_LEXER_ESM_SYNTAX';
  /** Character position in source where error occurred */
  loc: number;
  /** Standard error message describing the issue */
  message: string;
  /** Standard error name property */
  name: string;
}

try {
  parse('import { foo } from "bar";'); // ESM syntax in CJS
} catch (error) {
  console.log(error.code); // 'ERR_LEXER_ESM_SYNTAX'
  console.log(error.loc);  // Character position
  console.log(error.message); // 'Unexpected import statement in CJS module.'
}

try {
  parse('export const foo = "bar";'); // ESM export in CJS
} catch (error) {
  console.log(error.message); // 'Unexpected export statement in CJS module.'
}