try a require

Author: cnuss

src/index.ts

@@ -1,7 +1,8 @@
-import ServerlessWebpack from "serverless-webpack";
 import { Options, Serverless } from "./serverless-webpack";
 import path from "path";
 
+const ServerlessWebpack = require("serverless-webpack");
+
 class ServerlessReact extends ServerlessWebpack {
   hooks: {
     [key: string]: () => void;