Remove JSON.stringify used to encode HTML attributes in SSR. Replace with concatenation of double quotes before and after the value. Fixes #4240

src/runtime/internal/ssr.ts

@@ -25,9 +25,14 @@ export function spread(args, classes_to_add) {
 		else if (boolean_attributes.has(name.toLowerCase())) {
 			if (value) str += " " + name;
 		} else if (value != null) {
-			str += " " + name + "=" + JSON.stringify(String(value)
+			str +=
+				' ' +
+				name +
+				'="' +
+				String(value)
 					.replace(/"/g, '"')
-				.replace(/'/g, '''));
+					.replace(/'/g, ''') +
+				'"';
 		}
 	});
 

test/server-side-rendering/samples/spread-attributes-white-space/_expected.html

@@ -1,3 +1,8 @@
 <input value="
 	bar
-" />
+">
+
+<input class="
+	white
+	space
+">

test/server-side-rendering/samples/spread-attributes-white-space/main.svelte

@@ -5,3 +5,8 @@
 </script>
 
 <input {...props} />
+
+<input class="
+	white
+	space
+" {...({})}>