Index: src/wp-includes/js/wp-emoji.js
===================================================================
--- src/wp-includes/js/wp-emoji.js	(revision 31752)
+++ src/wp-includes/js/wp-emoji.js	(working copy)
@@ -52,6 +52,8 @@
 		 * @since 4.2.0
 		 */
 		load: function() {
+			emoji.parse( document.body );
+
 			if ( MutationObserver ) {
 				new MutationObserver( function( mutationRecords ) {
 					var i = mutationRecords.length,
@@ -80,8 +82,6 @@
 					subtree: true
 				} );
 			}
-
-			emoji.parse( document.body );
 		},
 
 		/**
@@ -172,7 +172,10 @@
 							return false;
 					}
 
-					if ( emoji.parseFlags && ! emoji.parseAllEmoji && ! icon.match( /^1f1(e[6-9a-f]|f[1-9a-f])-1f1(e[6-9a-f]|f[1-9a-f])$/ ) ) {
+					if (
+						emoji.parseFlags && ! emoji.parseAllEmoji &&
+						! /^1f1(?:e[6-9a-f]|f[1-9a-f])-1f1(?:e[6-9a-f]|f[1-9a-f])$/.test( icon )
+					) {
 						return false;
 					}