diff -r 490d5cc509ed -r cf61fcea0001 wp/wp-includes/js/shortcode.js
--- a/wp/wp-includes/js/shortcode.js	Tue Jun 09 11:14:17 2015 +0000
+++ b/wp/wp-includes/js/shortcode.js	Mon Oct 14 17:39:30 2019 +0200
@@ -1,6 +1,10 @@
 // Utility functions for parsing and handling shortcodes in JavaScript.
 
-// Ensure the global `wp` object exists.
+/**
+ * Ensure the global `wp` object exists.
+ *
+ * @namespace wp
+ */
 window.wp = window.wp || {};
 
 (function(){
@@ -134,8 +138,9 @@
 			// 5. An attribute name, that corresponds to...
 			// 6. an unquoted value.
 			// 7. A numeric attribute in double quotes.
-			// 8. An unquoted numeric attribute.
-			pattern = /(\w+)\s*=\s*"([^"]*)"(?:\s|$)|(\w+)\s*=\s*\'([^\']*)\'(?:\s|$)|(\w+)\s*=\s*([^\s\'"]+)(?:\s|$)|"([^"]*)"(?:\s|$)|(\S+)(?:\s|$)/g;
+			// 8. A numeric attribute in single quotes.
+			// 9. An unquoted numeric attribute.
+			pattern = /([\w-]+)\s*=\s*"([^"]*)"(?:\s|$)|([\w-]+)\s*=\s*'([^']*)'(?:\s|$)|([\w-]+)\s*=\s*([^\s'"]+)(?:\s|$)|"([^"]*)"(?:\s|$)|'([^']*)'(?:\s|$)|(\S+)(?:\s|$)/g;
 
 			// Map zero-width spaces to actual spaces.
 			text = text.replace( /[\u00a0\u200b]/g, ' ' );
@@ -152,6 +157,8 @@
 					numeric.push( match[7] );
 				} else if ( match[8] ) {
 					numeric.push( match[8] );
+				} else if ( match[9] ) {
+					numeric.push( match[9] );
 				}
 			}
 
@@ -326,11 +333,6 @@
 			_.each( options.attrs, function( value, attr ) {
 				text += ' ' + attr;
 
-				// Use empty attribute notation where possible.
-				if ( '' === value ) {
-					return;
-				}
-
 				// Convert boolean values to strings.
 				if ( _.isBoolean( value ) ) {
 					value = value ? 'true' : 'false';