fix: added necessary code

index.d.ts

@@ -0,0 +1,5 @@
+declare module "mongoose-lean-virtuals" {
+    import mongoose = require('mongoose');
+    export default function mongooseLeanVirtuals(schema: mongoose.Schema<any, any, any, any>, opts?: any): void;
+    export function mongooseLeanVirtuals(schema: mongoose.Schema<any, any, any, any>, opts?: any): void;
+  }

index.js

@@ -213,4 +213,7 @@ function attachVirtualsToDoc(schema, doc, virtuals) {
 
 function isPopulateVirtual(virtualType) {
   return virtualType.options && (virtualType.options.ref || virtualType.options.refPath);
-}
+}
+
+module.exports.defaults = module.exports;
+module.exports.mongooseLeanVirtuals = module.exports;

test/test.ts

@@ -0,0 +1,17 @@
+import * as mongoose from 'mongoose';
+import * as mongooseLeanVirtuals from "mongoose-lean-virtuals";
+
+interface Test {
+    name: string
+}
+/*
+const testSchema = new mongoose.Schema({
+    name: String
+});
+*/
+
+const testSchema = new mongoose.Schema<Test>({
+    name: String
+});
+
+testSchema.plugin(mongooseLeanVirtuals.mongooseLeanVirtuals);