Fix legacy build

The build process failed because webpack does not allow failed imports
when it is run as a module.
This detects modules with default exports and only generates import
statements for default exports where they are available.

config/jsdoc/plugins/virtual-plugin.cjs

@@ -0,0 +1,16 @@
+/* eslint-disable import/no-commonjs */
+
+/**
+ * Handle the interface and abstract annotations.
+ * @param {Object} dictionary The tag dictionary.
+ */
+exports.defineTags = function (dictionary) {
+  const classTag = dictionary.lookUp('class');
+  dictionary.defineTag('interface', {
+    mustNotHaveValue: true,
+    onTagged: function (doclet, tag) {
+      classTag.onTagged.apply(this, arguments);
+      doclet.virtual = true;
+    },
+  });
+};