View source: Cache stringification result

Author: Gabriel Schulhof

demos/_assets/js/view-source.js

@@ -53,9 +53,45 @@ function getSnippet( type, selector, source ) {
 		if ( el.length === 0 && type === "style" ) {
 			el = source.find( "link[rel='stylesheet']" + selector );
 		}
-		text = $( "<div></div>" )
-			.append( ( "markup" === type ? el : el.contents() ).clone() )
-			.html();
+
+		// Stringify each element and cache the string representation on the element. This helps us
+		// avoid re-stringifying the element later. This, in turn, prevents us from re-stringifying
+		// already enhanced elements, such as shared widgets outside the page, when the View Source
+		// button is in the page, and the elements have already been enhanced when the View Source
+		// button is created. This assumes, of course, that the first time we stringify an element
+		// the element is not yet enhanced.
+		el.each( function( index, singleElement ) {
+			var whitespace,
+				single = $( this ),
+				singleText = single.jqmData( "viewSourceCachedData" );
+
+			if ( !singleText ) {
+				singleText = $( "<div></div>" )
+						.append( ( "markup" === type ? single : single.contents() ).clone() )
+						.html();
+
+				// If we're dealing with markup, retrieve the initial indentation of the element so
+				// we get proper indentation in the source view
+				if ( type === "markup" ) {
+					if ( this.previousSibling && this.previousSibling.nodeType === 3 ) {
+						whitespace = $( "<div>" )
+							.append( $( this.previousSibling ).clone() )
+							.html()
+							.match( /\n(\s*)$/ );
+						if ( whitespace && whitespace.length > 1 ) {
+							singleText = whitespace[ 1 ] + singleText;
+						}
+					}
+				}
+				single.jqmData( "viewSourceCachedData", singleText );
+			}
+
+			text = text +
+
+				// Separate the text for multiple elements with a newline
+				( index > 0 ? "\n" : "" ) +
+				singleText;
+		});
 		if ( !text ) {
 			text = "";
 			selector = el.attr( "href" ) || el.attr( "src" ) || "";