[jquery] offset() can return undefined on empty sets.

types/jquery/index.d.ts

@@ -1368,7 +1368,7 @@ interface JQuery<TElement extends Node = HTMLElement> {
      * @see {@link https://api.jquery.com/offset/}
      * @since 1.2
      */
-    offset(): JQuery.Coordinates;
+    offset(): JQuery.Coordinates | undefined;
     /**
      * Get the closest ancestor element that is positioned.
      *

types/jquery/jquery-tests.ts

@@ -601,7 +601,7 @@ function JQuery() {
                 };
             });
 
-            // $ExpectType Coordinates
+            // $ExpectType Coordinates | undefined
             $('p').offset();
         }
 

types/jquery/test/example-tests.ts

@@ -3754,13 +3754,13 @@ function examples() {
 
     function offset_0() {
         var p = $('p:last');
-        var offset = p.offset();
+        var offset = p.offset()!;
         p.html('left: ' + offset.left + ', top: ' + offset.top);
     }
 
     function offset_1() {
         $('*', document.body).click(function(event) {
-            var offset = $(this).offset();
+            var offset = $(this).offset()!;
             event.stopPropagation();
             $('#result').text(this.tagName +
                 ' coords ( ' + offset.left + ', ' + offset.top + ' )');