add ability to await async callback functions

thumbnail.js

@@ -1,25 +1,38 @@
 class Thumbnail {
     static wrapImgInContainer(img, container_style_class) {
-        const container = document.createElement('div');
+        const container = document.createElement('div')
-        container.className = container_style_class;
+        container.className = container_style_class
-        container.appendChild(img);
+        container.appendChild(img)
-        return container;
+        return container
     }
 
-    static addSPButtonToContainer(container, button_id, title, callbackFunction, param1) {
+    static addSPButtonToContainer(
-        const elem = document.getElementById(button_id);
+        container,
-        const clone = elem.cloneNode(true);
+        button_id,
+        title,
+        callbackFunction,
+        param1
+    ) {
+        const elem = document.getElementById(button_id)
+        const clone = elem.cloneNode(true)
         const button = clone
         button.style.display = null
         button.removeAttribute('id')
         button.setAttribute('title', title)
 
         // Create button element
-        button.className = "thumbnail-image-button";
+        button.className = 'thumbnail-image-button'
-        button.addEventListener('click', () => callbackFunction(param1))
+        if (callbackFunction.constructor.name === 'AsyncFunction') {
+            button.addEventListener(
+                'click',
+                async () => await callbackFunction(param1)
+            )
+        } else {
+            button.addEventListener('click', () => callbackFunction(param1))
+        }
+
         container.appendChild(button)
     }
-
 }
 
 module.exports = {