feat: ESM modules support

lib/follow.ts

@@ -4,6 +4,7 @@ import { core, sync, SyncOpts } from 'resolve';
 import assert from 'assert';
 import fs from 'fs';
 import path from 'path';
+import { CachedInputFileSystem, ResolverFactory } from 'enhanced-resolve';
 import { toNormalizedRealPath } from './common';
 
 Object.keys(core).forEach((key) => {
@@ -119,3 +120,40 @@ export function follow(x: string, opts: FollowOptions) {
  );
  });
 }
+
+export function followESM(x: string, opts: FollowOptions) {
+ return new Promise<string>((resolve, reject) => {
+ const fileSystem = new CachedInputFileSystem(fs, 4000);
+
+ fileSystem.readFileSync = (file) => {
+ if (opts.ignoreFile && opts.ignoreFile === file) {
+ return Buffer.from(`{"main":"${PROOF}"}`);
+ }
+
+ if (opts.readFile) {
+ opts.readFile(file);
+ }
+
+ return fs.readFileSync(file);
+ }
+
+ const resolver = ResolverFactory.createResolver({
+ extensions: opts.extensions as string[],
+ fileSystem
+ });
+
+ const lookupStartPath :string = opts.basedir || __dirname;
+ const context = {};
+ const resolveContext = {};
+
+ resolver.resolve(context, lookupStartPath, x, resolveContext, (err, result) => {
+ if(!result || err) {
+ reject(err || Error(`Cannot resolve ${x}`))
+ } else {
+ resolve(result);
+ }
+ });
+
+
+ });
+}

lib/walker.ts

@@ -21,7 +21,7 @@ import {
  toNormalizedRealPath,
 } from './common';
 
-import { follow, natives } from './follow';
+import { follow, followESM, natives } from './follow';
 import { log, wasReported } from './log';
 import * as detector from './detector';
 import {
@@ -752,7 +752,7 @@ class Walker {
 
  const basedir = path.dirname(record.file);
  try {
- newFile = await follow(derivative.alias, {
+ newFile = await followESM(derivative.alias, {
  basedir,
  // default is extensions: ['.js'], but
  // it is not enough because 'typos.json'

package.json

@@ -20,6 +20,7 @@
  "@babel/parser": "7.13.13",
  "@babel/types": "7.13.12",
  "chalk": "^4.1.0",
+ "enhanced-resolve": "5.8.3",
  "escodegen": "^2.0.0",
  "fs-extra": "^9.1.0",
  "globby": "^11.0.3",

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'));

yarn.lock

@@ -868,6 +868,14 @@ end-of-stream@^1.1.0, end-of-stream@^1.4.1:
  dependencies:
  once "^1.4.0"
 
+enhanced-resolve@5.8.3:
+ version "5.8.3"
+ resolved "https://registry.yarnpkg.com/enhanced-resolve/-/enhanced-resolve-5.8.3.tgz#6d552d465cce0423f5b3d718511ea53826a7b2f0"
+ integrity sha512-EGAbGvH7j7Xt2nc0E7D99La1OiEs8LnyimkRgwExpUMScN6O+3x9tIWs7PLQZVNx4YD+00skHXPXi1yQHpAmZA==
+ dependencies:
+ graceful-fs "^4.2.4"
+ tapable "^2.2.0"
+
 enquirer@^2.3.5, enquirer@^2.3.6:
  version "2.3.6"
  resolved "https://registry.npmjs.org/enquirer/-/enquirer-2.3.6.tgz"
@@ -1370,6 +1378,11 @@ graceful-fs@^4.1.6, graceful-fs@^4.2.0:
  resolved "https://registry.npmjs.org/graceful-fs/-/graceful-fs-4.2.3.tgz"
  integrity sha512-a30VEBm4PEdx1dRB7MFK7BejejvCvBronbLjht+sHuGYj8PHs7M/5Z+rt5lw551vZ7yfTCj4Vuyy3mSJytDWRQ==
 
+graceful-fs@^4.2.4:
+ version "4.2.8"
+ resolved "https://registry.yarnpkg.com/graceful-fs/-/graceful-fs-4.2.8.tgz#e412b8d33f5e006593cbd3cee6df9f2cebbe802a"
+ integrity sha512-qkIilPUYcNhJpd33n0GBXTB1MMPp14TxEsEs0pTrsSVucApsYzW5V+Q8Qxhik6KU3evy+qkAAowTByymK0avdg==
+
 has-bigints@^1.0.1:
  version "1.0.1"
  resolved "https://registry.npmjs.org/has-bigints/-/has-bigints-1.0.1.tgz"
@@ -2603,6 +2616,11 @@ table@^6.0.9:
  string-width "^4.2.0"
  strip-ansi "^6.0.0"
 
+tapable@^2.2.0:
+ version "2.2.1"
+ resolved "https://registry.yarnpkg.com/tapable/-/tapable-2.2.1.tgz#1967a73ef4060a82f12ab96af86d52fdb76eeca0"
+ integrity sha512-GNzQvQTOIP6RyTfE2Qxb8ZVlNmw0n88vp1szwWRimP02mnTsx3Wtn5qRdqY9w2XduFNUgvOwhNnQsjwCp+kqaQ==
+
 tar-fs@^2.0.0:
  version "2.1.1"
  resolved "https://registry.npmjs.org/tar-fs/-/tar-fs-2.1.1.tgz"