feat: ESM modules support

test/test-00-esm/main.cjs

@@ -0,0 +1,47 @@
+#!/usr/bin/env node
+
+'use strict';
+
+const path = require('path');
+const assert = require('assert');
+const utils = require('../utils.js');
+const os = require('os');
+
+const MAJOR_VERSION = parseInt(process.version.match(/v([0-9]+)/)[1], 10);
+
+if (MAJOR_VERSION < 14) {
+  console.log(
+    'skiping test as it requires nodejs >= 14',
+    MAJOR_VERSION
+  );
+  return;
+}
+
+assert(__dirname === process.cwd());
+
+const ext = process.platform === 'win32' ? '.exe' : '';
+
+const target = process.argv[2] || 'host';
+const input = './test.js';
+const output = './test-output' + ext;
+
+console.log('target = ', target);
+utils.pkg.sync([
+  '--target',
+  target,
+  '--output',
+  output,
+  input,
+]);
+
+// check that produced executable is running and produce the expected output.
+const log = utils.spawn.sync(output, [], {
+  cwd: path.dirname(output),
+  expect: 0,
+});
+assert(log === os.arch() + '\n');
+
+// clean up
+utils.vacuum.sync(output);
+
+console.log('OK');

test/test-00-esm/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "test-00-esm",
+  "version": "1.0.0",
+  "description": "",
+  "type": "module",
+  "main": "test.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC"
+}

test/test-00-esm/test.js

@@ -0,0 +1,3 @@
+import os from 'os';
+
+console.log(os.arch());

test/test.js

@@ -49,11 +49,14 @@ function joinAndForward(d) {
 const list = [];
 
 if (flavor.match(/^test/)) {
-  list.push(joinAndForward(`${flavor}/main.js`));
+  list.push(
+    joinAndForward(`${flavor}/main.js`),
+    joinAndForward(`${flavor}/main.cjs`)
+  );
 } else if (flavor === 'only-npm') {
   list.push(joinAndForward('test-79-npm/main.js'));
 } else {
-  list.push(joinAndForward('**/main.js'));
+  list.push(joinAndForward('**/main.js'), joinAndForward('**/main.cjs'));
   if (flavor === 'no-npm') {
     list.push('!' + joinAndForward('test-42-fetch-all'));
     list.push('!' + joinAndForward('test-46-multi-arch'));