diff --git a/src/slicer.worker.js b/src/slicer.worker.js
index 7c0bc37..59bb2ce 100644
--- a/src/slicer.worker.js
+++ b/src/slicer.worker.js
@@ -1,3 +1,4 @@
+import 'core-js'; // polyfills
 import slice from './sliceActions/slice.js';
 import * as THREE from 'three';