info-modal: Don't crash for layers with unknown sources or URLs.

1 files changed, 2 insertions, 2 deletions

diff --git a/main.js b/main.js
index 661a17e..c1c7da9 100644
--- a/main.js
+++ b/main.js
@@ -539,10 +539,10 @@ if (window.location === window.parent.location) {
     infoMetadataAccordions.forEach((x) => x.element.replaceChildren());
     modal.show();
     Promise.allSettled(Object.entries(mapLayers).map(function([grp,lyr]) {
-      if (lyr.getSource() instanceof VectorTile) {
+      if (lyr !== null && lyr.getSource() instanceof VectorTile) {
         const url = lyr.getSource().getUrls()[0];
         if (url === undefined || url.length <= 16 || url.substr(url.length - 16) !== '/{z}/{x}/{y}.pbf') {
-          throw new Error(`Invalid URL ${url}`);
+          return new Promise(() => { throw new Error(`Invalid URL ${url}`); });
         }
         return fetch(url.substr(0, url.length - 16) + '/metadata.json')
           .then(function(resp0) {