bug fix:

bug:
when an item is dragged fast enough before the previous request was
completed, dropping after request completion resulted in the addition
of an extra item to the list.

fix:
disable sortable on End event, and re-enable it on htmx:afterSwap.

www/content/examples/sortable.md

@@ -57,15 +57,21 @@ That's it!
     htmx.onLoad(function(content) {
         var sortables = content.querySelectorAll(".sortable");
         for (var i = 0; i < sortables.length; i++) {
-          var sortable = sortables[i];
-          new Sortable(sortable, {
+          var sortableList = sortables[i];
+          sortable = new Sortable(sortableList, {
               animation: 150,
               ghostClass: 'blue-background-class',
               filter: ".htmx-indicator",
               onMove: function (evt) {
                 return evt.related.className.indexOf('htmx-indicator') === -1;
+              },
+              onEnd: function (evt) {
+                this.option("disabled", true);
               }
           });
+          sortableList.addEventListener("htmx:afterSwap", function() {
+            sortable.option("disabled", false);
+          });
         }
     })