Switched to type: module.

rollup.tracker.config.js

@@ -0,0 +1,20 @@
+import 'dotenv/config';
+import replace from '@rollup/plugin-replace';
+import terser from '@rollup/plugin-terser';
+
+export default {
+  input: 'src/tracker/index.js',
+  output: {
+    file: 'public/script.js',
+    format: 'iife',
+  },
+  plugins: [
+    replace({
+      __COLLECT_API_HOST__: process.env.COLLECT_API_HOST || '',
+      __COLLECT_API_ENDPOINT__: process.env.COLLECT_API_ENDPOINT || '/api/send',
+      delimiters: ['', ''],
+      preventAssignment: true,
+    }),
+    terser({ compress: { evaluate: false } }),
+  ],
+};