use temporary variable when determining whether to update text tag

src/generators/dom/index.js

@@ -71,6 +71,8 @@ class DomGenerator extends Generator {
 		} else {
 			properties.addBlock( deindent`
 				update: function ( changed, ${fragment.params} ) {
+					var __tmp;
+
 					${fragment.builders.update}
 				},
 			` );

src/generators/dom/visitors/MustacheTag.js

@@ -7,13 +7,13 @@ export default {
 		generator.addSourcemapLocations( node.expression );
 		const { snippet } = generator.contextualise( node.expression );
 
+		generator.current.builders.init.addLine( `var last_${name} = ${snippet}` );
+		generator.addElement( name, `createText( last_${name} )`, true );
 		generator.uses.createText = true;
-		generator.addElement( name, `createText( ${snippet} )`, true );
-		generator.current.builders.init.addLine(`var last_${name} = ${snippet}`);
 
 		generator.current.builders.update.addBlock( deindent`
-			if (${snippet} !== last_${name}) {
-				${name}.data = last_${name} = ${snippet};
+			if ( ( __tmp = ${snippet} ) !== last_${name} ) {
+				${name}.data = last_${name} = __tmp;
 			}
 		` );
 	}