1 files changed, 24 insertions, 11 deletions
diff --git a/lib/internal/bootstrap/node.js b/lib/internal/bootstrap/node.js
index dec4f12ea6..8f38bff448 100644
--- a/lib/internal/bootstrap/node.js
+++ b/lib/internal/bootstrap/node.js
@@ -240,17 +240,6 @@ function startup() {
       'DeprecationWarning', 'DEP0062', startup, true);
   }
 
-  const experimentalModules = getOptionValue('--experimental-modules');
-  const experimentalVMModules = getOptionValue('--experimental-vm-modules');
-  if (experimentalModules || experimentalVMModules) {
-    if (experimentalModules) {
-      process.emitWarning(
-        'The ESM module loader is experimental.',
-        'ExperimentalWarning', undefined);
-    }
-    NativeModule.require('internal/process/esm_loader').setup();
-  }
-
   const { deprecate } = NativeModule.require('internal/util');
   {
     // Install legacy getters on the `util` binding for typechecking.
@@ -445,6 +434,30 @@ function prepareUserCodeExecution() {
     delete process.env.NODE_UNIQUE_ID;
   }
 
+  const experimentalModules = getOptionValue('--experimental-modules');
+  const experimentalVMModules = getOptionValue('--experimental-vm-modules');
+  if (experimentalModules || experimentalVMModules) {
+    if (experimentalModules) {
+      process.emitWarning(
+        'The ESM module loader is experimental.',
+        'ExperimentalWarning', undefined);
+    }
+
+    const {
+      setImportModuleDynamicallyCallback,
+      setInitializeImportMetaObjectCallback
+    } = internalBinding('module_wrap');
+    const esm = NativeModule.require('internal/process/esm_loader');
+    // Setup per-isolate callbacks that locate data or callbacks that we keep
+    // track of for different ESM modules.
+    setInitializeImportMetaObjectCallback(esm.initializeImportMetaObject);
+    setImportModuleDynamicallyCallback(esm.importModuleDynamicallyCallback);
+    const userLoader = getOptionValue('--loader');
+    // If --loader is specified, create a loader with user hooks. Otherwise
+    // create the default loader.
+    esm.initializeLoader(process.cwd(), userLoader);
+  }
+
   // For user code, we preload modules if `-r` is passed
   const preloadModules = getOptionValue('--require');
   if (preloadModules) {