Make vite work out-of-the-box for simple-host (#33)

examples/simple-host/vite.config.ts

@@ -1,24 +1,24 @@
 import { defineConfig } from "vite";
 import react from "@vitejs/plugin-react";
-import { viteSingleFile } from "vite-plugin-singlefile";
 
-const INPUT = process.env.INPUT;
-if (!INPUT) {
-  throw new Error("INPUT environment variable is not set");
-}
-
-const isDevelopment = process.env.NODE_ENV === "development";
-
-export default defineConfig({
-  plugins: [react(), viteSingleFile()],
-  build: {
-    sourcemap: isDevelopment ? "inline" : undefined,
-    cssMinify: !isDevelopment,
-    minify: !isDevelopment,
-    rollupOptions: {
-      input: INPUT,
+export default defineConfig(({ mode }) => {
+  const isDevelopment = mode === "development";
+  return {
+    plugins: [react()],
+    build: {
+      sourcemap: isDevelopment ? "inline" : undefined,
+      cssMinify: !isDevelopment,
+      minify: !isDevelopment,
+      rollupOptions: {
+        input: [
+          "index.html",
+          "example-host-vanilla.html",
+          "example-host-react.html",
+          "sandbox.html",
+        ],
+      },
+      outDir: `dist`,
+      emptyOutDir: false,
     },
-    outDir: `dist`,
-    emptyOutDir: false,
-  },
+  };
 });