esm: handle globalPreload hook returning a nullish value

Author: aduh95

lib/internal/modules/esm/hooks.js

@@ -169,7 +169,7 @@ class Hooks {
         port: insideLoader,
       });
 
-      if (preloaded == null) { return; }
+      if (preloaded == null) { continue; }
 
       if (typeof preloaded !== 'string') { // [2]
         throw new ERR_INVALID_RETURN_VALUE(

test/es-module/test-esm-loader-hooks.mjs

@@ -244,6 +244,20 @@ describe('Loader hooks', { concurrency: true }, () => {
     assert.strictEqual(signal, null);
   });
 
+  it('should handle globalPreload returning undefined', async () => {
+    const { code, signal, stdout, stderr } = await spawnPromisified(execPath, [
+      '--no-warnings',
+      '--experimental-loader',
+      'data:text/javascript,export function globalPreload(){}',
+      fixtures.path('empty.js'),
+    ]);
+
+    assert.strictEqual(stderr, '');
+    assert.strictEqual(stdout, '');
+    assert.strictEqual(code, 0);
+    assert.strictEqual(signal, null);
+  });
+
   it('should be fine to call `process.removeAllListeners("beforeExit")` from the main thread', async () => {
     const { code, signal, stdout, stderr } = await spawnPromisified(execPath, [
       '--no-warnings',