diff --git a/main.js b/main.js
index db3d16f..f6b3f37 100644
--- a/main.js
+++ b/main.js
@@ -130,7 +130,7 @@ for (let category of layerCategories) {
 }
 
 const urlParams = qs.parse(window.location.search, { ignoreQueryPrefix: true });
-const urlLayers = urlParams.layer ?? [];
+const urlLayers = ('layer' in urlParams) ? (typeof urlParams.layer === 'string' ? [urlParams.layer] : urlParams.layer) : [];
 
 for (let category of layerCategories) {
   for (let layer of category.layers) {