fix element spread SSR

Author: Rich-Harris

src/generators/server-side-rendering/visitors/Element.ts

@@ -56,7 +56,7 @@ export default function visitElement(
 					block.contextualise(attribute.value[0].expression);
 					args.push(`{ ${quoteIfNecessary(attribute.name)}: ${attribute.value[0].metadata.snippet} }`);
 				} else {
-					args.push(`{ ${quoteIfNecessary(attribute.name)}: "${stringifyAttributeValue(block, attribute.value)}" }`);
+					args.push(`{ ${quoteIfNecessary(attribute.name)}: \`${stringifyAttributeValue(block, attribute.value)}\` }`);
 				}
 			}
 		});

test/runtime/samples/spread-element-multiple/_config.js

@@ -0,0 +1,33 @@
+export default {
+	data: {
+		a: {
+			'data-one': 1,
+			'data-two': 2,
+		},
+		c: {
+			'data-b': 'overridden',
+		},
+		d: 'deeeeee',
+	},
+
+	html: `
+		<div data-one="1" data-two="2" data-b="overridden" data-d="deeeeee" >test</div>
+	`,
+
+	test(assert, component, target) {
+		component.set({
+			a: {
+				'data-one': 10
+			},
+			c: {
+				'data-c': 'new'
+			},
+			d: 'DEEEEEE'
+		});
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`<div data-one="10" data-b="b" data-c="new" data-d="DEEEEEE" >test</div>`
+		);
+	},
+};

test/runtime/samples/spread-element-multiple/main.html

@@ -0,0 +1 @@
+<div {{...a}} data-b="b" {{...c}} data-d={{d}} >test</div>