Ticket #46280: 46280.diff

src/js/_enqueues/lib/comment-reply.js

@@ -10 +10 @@
  */
 window.addComment = ( function( window ) {
         // Avoid scope lookups on commonly used variables.
-        var document = window.document;
+        var document;
 
         // Settings.
         var config = {
@@ -23 +23 @@
         };
 
         // Cross browser MutationObserver.
-        var MutationObserver = window.MutationObserver || window.WebKitMutationObserver || window.MozMutationObserver;
+        var MutationObserver;
 
         // Check browser cuts the mustard.
-        var cutsTheMustard = 'querySelector' in document && 'addEventListener' in window;
+        var cutsTheMustard;
 
-        /*
-         * Check browser supports dataset.
-         * !! sets the variable to true if the property exists.
-         */
-        var supportsDataset = !! document.body.dataset;
+        // Check browser supports dataset.
+        var supportsDataset;
 
         // For holding the cancel element.
         var cancelElement;
@@ -46 +43 @@
         // The mutation observer.
         var observer;
 
-        // Initialise the events.
-        init();
+        if ( window.document && window.document.body ) {
+                ready();
+        } else if ( window.addEventListener ) {
+                window.addEventListener( 'DOMContentLoaded', ready, false );
+        }
+
+        /**
+         * Sets up object variables after the DOM is ready.
+         *
+         * @since 5.1.0
+         */
+        function ready() {
+                document = window.document;
+
+                MutationObserver = window.MutationObserver || window.WebKitMutationObserver || window.MozMutationObserver;
+
+                // Check browser cuts the mustard.
+                cutsTheMustard = 'querySelector' in document && 'addEventListener' in window;
 
-        // Set up a MutationObserver to check for comments loaded late.
-        observeChanges();
+                // !! sets the variable to true if the property exists.
+                supportsDataset = !! document.body.dataset;
+
+                // Initialise the events.
+                init();
+
+                // Set up a MutationObserver to check for comments loaded late.
+                observeChanges();
+        }
 
         /**
          * Add events to links classed .comment-reply-link.