Minor fixes

src/editor/Editor.jsx

@@ -57,7 +57,7 @@ const Editor = props => {
   }, [ props.annotation, props.selectedElement, bounds(props.selectedElement) ]);
 
   const initResizeObserver = () => {
-    if (window.ResizeObserver) {
+    if (window?.ResizeObserver) {
       const resizeObserver = new ResizeObserver(() => {
         setPosition(props.wrapperEl, element.current, props.selectedElement);
       });

src/utils/index.js

@@ -72,6 +72,53 @@ export const addPolyfills = () => {
     };
   }
 
+  if (!Array.prototype.find) {
+    Object.defineProperty(Array.prototype, 'find', {
+      value: function(predicate) {
+        // 1. Let O be ? ToObject(this value).
+        if (this == null) {
+          throw TypeError('"this" is null or not defined');
+        }
+  
+        var o = Object(this);
+  
+        // 2. Let len be ? ToLength(? Get(O, "length")).
+        var len = o.length >>> 0;
+  
+        // 3. If IsCallable(predicate) is false, throw a TypeError exception.
+        if (typeof predicate !== 'function') {
+          throw TypeError('predicate must be a function');
+        }
+  
+        // 4. If thisArg was supplied, let T be thisArg; else let T be undefined.
+        var thisArg = arguments[1];
+  
+        // 5. Let k be 0.
+        var k = 0;
+  
+        // 6. Repeat, while k < len
+        while (k < len) {
+          // a. Let Pk be ! ToString(k).
+          // b. Let kValue be ? Get(O, Pk).
+          // c. Let testResult be ToBoolean(? Call(predicate, T, « kValue, k, O »)).
+          // d. If testResult is true, return kValue.
+          var kValue = o[k];
+          if (predicate.call(thisArg, kValue, k, o)) {
+            return kValue;
+          }
+          // e. Increase k by 1.
+          k++;
+        }
+  
+        // 7. Return undefined.
+        return undefined;
+      },
+      configurable: true,
+      writable: true
+    });
+    
+  }
+
 }
 
 /**