Port to ESM

.eslintrc

@@ -6,20 +6,13 @@
   "extends": ["eslint:recommended", "plugin:import/errors", "plugin:import/warnings"],
   "plugins": ["import"],
   "parserOptions": {
-    "ecmaVersion": 11
+    "ecmaVersion": 13,
+    "sourceType": "module"
   },
   "rules": {
     "eqeqeq": "error",
     "no-trailing-spaces": "error",
     "prefer-arrow-callback": "error",
     "semi": "error"
-  },
-  "overrides": [
-    {
-      "files": ["./**/*.mjs"],
-      "parserOptions": {
-        "sourceType": "module"
-      }
-    }
-  ]
+  }
 }

bin/node-dev.js

@@ -0,0 +1,8 @@
+#!/usr/bin/env node
+
+import dev from '../lib/index.js';
+import cli from '../lib/cli.js';
+
+const { script, scriptArgs, nodeArgs, opts } = cli(process.argv);
+
+dev(script, scriptArgs, nodeArgs, opts);

lib/clear.js

@@ -1,4 +1,2 @@
-const control = '\u001bc';
-const clearFactory = clear => (clear ? () => process.stdout.write(control) : () => {});
-
-module.exports = { clearFactory, control };
+export const control = '\u001bc';
+export const clearFactory = clear => (clear ? () => process.stdout.write(control) : () => {});

lib/cli.js

@@ -1,8 +1,8 @@
-const assert = require('assert');
-const minimist = require('minimist');
-const { resolve } = require('path');
+import assert from 'assert';
+import minimist from 'minimist';
+import { resolve } from 'path';
 
-const { getConfig } = require('./cfg');
+import { getConfig } from './cfg.cjs';
 
 const arrayify = v => (Array.isArray(v) ? [...v] : [v]);
 const argify = key => ({ arg: `--${key}`, key });
@@ -55,7 +55,7 @@ const unknownFactory = args => arg => {
   key && !nodeDevNumber.includes(key) && args.push({ arg, key });
 };
 
-module.exports = argv => {
+export default argv => {
   const nodeCustomArgs = [];
   const args = argv.slice(2).filter(nodeCustomFactory(nodeCustomArgs));
 

lib/ignore.js

@@ -18,7 +18,5 @@ const getPrefix = mod => {
 
 const isPrefixOf = value => prefix => value.startsWith(prefix);
 
-const configureDeps = deps => required => deps !== -1 && getLevel(required) > deps;
-const configureIgnore = ignore => required => ignore.some(isPrefixOf(required));
-
-module.exports = { configureDeps, configureIgnore };
+export const configureDeps = deps => required => deps !== -1 && getLevel(required) > deps;
+export const configureIgnore = ignore => required => ignore.some(isPrefixOf(required));

lib/index.js

@@ -1,15 +1,18 @@
-const { fork } = require('child_process');
-const filewatcher = require('filewatcher');
-const semver = require('semver');
-const { pathToFileURL } = require('url');
-
-const { clearFactory } = require('./clear');
-const { configureDeps, configureIgnore } = require('./ignore');
-const ipc = require('./ipc');
-const logFactory = require('./log');
-const notifyFactory = require('./notify');
-
-module.exports = function (
+import { fork } from 'child_process';
+import filewatcher from 'filewatcher';
+import { createRequire } from 'module';
+import semver from 'semver';
+
+import { clearFactory } from './clear.js';
+import { configureDeps, configureIgnore } from './ignore.js';
+import ipc from './ipc.cjs';
+import logFactory from './log.js';
+import notifyFactory from './notify.js';
+
+const require = createRequire(import.meta.url);
+const resolveHook = hook => require.resolve('./require/' + hook);
+
+export default function (
   script,
   scriptArgs,
   nodeArgs,
@@ -18,13 +21,15 @@ module.exports = function (
     debounce,
     dedupe,
     deps,
+    fork: patchFork,
     graceful_ipc: gracefulIPC,
     ignore,
     interval,
     notify: notifyEnabled,
     poll: forcePolling,
     respawn,
-    timestamp
+    timestamp,
+    vm: patchVm
   }
 ) {
   if (!script) {
@@ -52,9 +57,6 @@ module.exports = function (
   const isIgnored = configureIgnore(ignore);
   const isTooDeep = configureDeps(deps);
 
-  // Run ./dedupe.js as preload script
-  if (dedupe) process.env.NODE_DEV_PRELOAD = require.resolve('./dedupe');
-
   const watcher = filewatcher({ debounce, forcePolling, interval });
   let isPaused = false;
 
@@ -89,12 +91,16 @@ module.exports = function (
   function start() {
     isPaused = false;
 
-    const args = nodeArgs.slice();
+    const execArgv = nodeArgs.slice();
 
-    args.push(`--require=${require.resolve('./wrap')}`);
+    execArgv.push(`--require=${resolveHook('suppress-experimental-warnings')}`);
+    if (dedupe) execArgv.push(`--require=${resolveHook('dedupe')}`);
+    execArgv.push(`--require=${resolveHook('patch')}`);
+    if (patchFork) execArgv.push(`--require=${resolveHook('patch-fork')}`);
+    if (patchVm) execArgv.push(`--require=${resolveHook('patch-vm')}`);
 
     if (semver.satisfies(process.version, '<12.17.0')) {
-      args.push('--experimental-modules');
+      execArgv.push('--experimental-modules');
     }
 
     const loaderName = semver.satisfies(process.version, '>=16.12.0')
@@ -103,18 +109,18 @@ module.exports = function (
       ? 'get-format'
       : 'resolve';
 
-    const loaderURL = pathToFileURL(require.resolve(`./loaders/${loaderName}.mjs`));
+    const loaderURL = new URL(`./loaders/${loaderName}.mjs`, import.meta.url);
 
     const experimentalPrefix = semver.satisfies(process.version, '>=12.11.1')
       ? 'experimental-'
       : '';
 
-    args.push(`--${experimentalPrefix}loader=${loaderURL.href}`);
+    execArgv.push(`--${experimentalPrefix}loader=${loaderURL.href}`);
 
     child = fork(script, scriptArgs, {
       cwd: process.cwd(),
       env: process.env,
-      execArgv: args
+      execArgv
     });
 
     if (respawn) {
@@ -167,4 +173,4 @@ module.exports = function (
 
   clearOutput();
   start();
-};
+}

lib/loaders/get-format.mjs

@@ -1,6 +1,6 @@
 import { createRequire } from 'module';
 import { fileURLToPath } from 'url';
-import { send } from './ipc.mjs';
+import { send } from '../ipc.cjs';
 
 const require = createRequire(import.meta.url);
 

lib/loaders/load.mjs

@@ -1,6 +1,6 @@
 import { createRequire } from 'module';
 import { fileURLToPath } from 'url';
-import { send } from './ipc.mjs';
+import { send } from '../ipc.cjs';
 
 const require = createRequire(import.meta.url);
 

lib/loaders/resolve.mjs

@@ -1,5 +1,5 @@
 import { fileURLToPath } from 'url';
-import { send } from './ipc.mjs';
+import { send } from '../ipc.cjs';
 
 export function resolve(specifier, parentModule, defaultResolve) {
   const resolved = defaultResolve(specifier, parentModule);

lib/log.js

@@ -1,5 +1,5 @@
-const { format } = require('util');
-const dateformat = require('dateformat');
+import { format } from 'util';
+import dateformat from 'dateformat';
 
 const colors = {
   error: '31;1',
@@ -16,7 +16,7 @@ const colorOutput = (s, c) => '\x1B[' + c + 'm' + s + '\x1B[0m';
  * Logs a message to the console. The level is displayed in ANSI colors:
  * errors are bright red, warnings are yellow, and info is cyan.
  */
-module.exports = ({ noColor, timestamp }) => {
+export default ({ noColor, timestamp }) => {
   const enableColor = !(noColor || !process.stdout.isTTY);
   const color = enableColor ? colorOutput : noop;
 

lib/notify.js

@@ -1,9 +1,11 @@
-const notifier = require('node-notifier');
+import notifier from 'node-notifier';
+import { fileURLToPath } from 'url';
 
-const iconLevelPath = level => require.resolve(`../icons/node_${level}.png`);
+const iconLevelPath = level =>
+  fileURLToPath(new URL(`../icons/node_${level}.png`, import.meta.url));
 
 // Writes a message to the console and optionally displays a desktop notification.
-module.exports = (notifyEnabled, log) => {
+export default (notifyEnabled, log) => {
   return (title = 'node-dev', message, level = 'info') => {
     log[level](`${title}: ${message}`);
 

lib/require/package.json

@@ -0,0 +1,3 @@
+{
+  "type": "commonjs"
+}

lib/require/patch-fork.js

@@ -0,0 +1,11 @@
+const childProcess = require('child_process');
+const { relay } = require('../ipc.cjs');
+
+// Overwrite child_process.fork() so that we can hook into forked processes
+// too. We also need to relay messages about required files to the parent.
+const { fork } = childProcess;
+childProcess.fork = (modulePath, args, options) => {
+  const child = fork(modulePath, args, options);
+  relay(child);
+  return child;
+};

lib/require/patch-vm.js

@@ -0,0 +1,25 @@
+const vm = require('vm');
+const { send } = require('../ipc.cjs');
+
+patch(vm, 'createScript', 1);
+patch(vm, 'runInThisContext', 1);
+patch(vm, 'runInNewContext', 2);
+patch(vm, 'runInContext', 2);
+
+/**
+ * Patch the specified method to watch the file at the given argument
+ * index.
+ */
+function patch(obj, method, optionsArgIndex) {
+  const orig = obj[method];
+  if (!orig) return;
+  obj[method] = function () {
+    const opts = arguments[optionsArgIndex];
+    let file = null;
+    if (opts) {
+      file = typeof opts === 'string' ? opts : opts.filename;
+    }
+    if (file) send({ required: file });
+    return orig.apply(this, arguments);
+  };
+}