Make esm support optional

Author: airhorns

integration-test/cjs-with-esm-disabled/.swcrc

@@ -0,0 +1,15 @@
+{
+  "jsc": {
+    "parser": {
+      "syntax": "typescript",
+      "tsx": true,
+      "decorators": true,
+      "dynamicImport": true
+    },
+    "target": "esnext"
+  },
+  "module": {
+    "type": "commonjs",
+    "lazy": true
+  }
+}

integration-test/cjs-with-esm-disabled/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "simple",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "type": "commonjs",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "license": "ISC"
+}

integration-test/cjs-with-esm-disabled/run.ts

@@ -0,0 +1,3 @@
+import { utility } from "./utils";
+
+console.log(utility("It worked!"));

integration-test/cjs-with-esm-disabled/test.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
+set -ex
+
+$DIR/../../pkg/wds.bin.js $@ $DIR/run.ts | grep "IT WORKED"

integration-test/cjs-with-esm-disabled/utils.ts

@@ -0,0 +1 @@
+export const utility = (str: string) => str.toUpperCase();

integration-test/cjs-with-esm-disabled/wds.js

@@ -0,0 +1,3 @@
+module.exports = {
+    esm: false,
+};

src/Options.ts

@@ -11,6 +11,7 @@ export interface RunOptions {
 export interface ProjectConfig {
   ignore: string[];
   swc?: SwcConfig;
+  esm?: boolean;
   extensions: string[];
   cacheDir: string;
 }

src/Supervisor.ts

@@ -1,6 +1,7 @@
 import type { ChildProcess, StdioOptions } from "child_process";
 import { spawn } from "child_process";
 import { EventEmitter, once } from "events";
+import _ from "lodash";
 import { setTimeout } from "timers/promises";
 import type { RunOptions } from "./Options.js";
 import type { Project } from "./Project.js";
@@ -66,6 +67,7 @@ export class Supervisor extends EventEmitter {
         ...process.env,
         WDS_SOCKET_PATH: this.socketPath,
         WDS_EXTENSIONS: this.project.config.extensions.join(","),
+        WDS_ESM_ENABLED: _.defaultTo(this.project.config.esm, true) ? "true" : "false",
       },
       stdio: stdio,
       detached: true,

src/hooks/child-process-register.ts

@@ -2,6 +2,7 @@
  * Entrypoint file passed as --import to all child processes started by wds
  */
 import { register } from "node:module";
+import { debugLog } from "../SyncWorker.cjs";
 
 if (!register) {
   throw new Error(
@@ -15,5 +16,8 @@ process.setSourceMapsEnabled(true);
 // register the CJS hook to intercept require calls the old way
 import "./child-process-cjs-hook.cjs";
 
-// register the ESM loader the new way
-register("./child-process-esm-loader.js", import.meta.url);
+if (process.env.WDS_ESM_ENABLED === "true") {
+  debugLog?.("registering wds ESM loader");
+  // register the ESM loader the new way
+  register("./child-process-esm-loader.js", import.meta.url);
+}