Replace more `=== undefined` with `== null`.

Cf. 887c24b79489fc9403a98a039a9138e48fc147a7.

1 files changed, 3 insertions, 3 deletions

diff --git a/main.js b/main.js
index af0e874..ff7dec9 100644
--- a/main.js
+++ b/main.js
@@ -3403,7 +3403,7 @@ const layerHierarchy = [
     }
 
     elem._legend = li;
-    if (elem.children !== undefined && elem.children.length > 0) {
+    if (elem.children != null && elem.children.length > 0) {
       if (classes.length > 0) {
         li.classList.add(classes[0]);
         classes = classes.slice(1);
@@ -3449,7 +3449,7 @@ const infoMetadataAccordions = [];
       elem._layers = elem.layer === undefined ? []
                    : Array.isArray(elem.layer) ? elem.layer
                    : [elem.layer];
-      if (elem.children !== undefined && elem.children.length > 0) {
+      if (elem.children != null && elem.children.length > 0) {
         collectLayers(elem.children);
         elem.children.forEach(function(child) {
           child._layers.forEach((l) => elem._layers.push(l));
@@ -3580,7 +3580,7 @@ const infoMetadataAccordions = [];
       const textNode = document.createTextNode(child.text);
       label.appendChild(textNode);
 
-      if (child.children !== undefined && child.children.length > 0) {
+      if (child.children != null && child.children.length > 0) {
         addAccordionGroup(li, child.children);
       }