failing SSR test, plus some adjacent changes

src/compiler/compile/render_ssr/handlers/Element.ts

@@ -140,8 +140,7 @@ export default function(node: Element, renderer: Renderer, options: RenderOption
 			} else if (attribute.chunks.length === 1 && attribute.chunks[0].type !== 'Text') {
 				const { name } = attribute;
 				const snippet = snip(attribute.chunks[0]);
-
+				opening_tag += '${@add_attribute("' + name + '", ' + snippet + ')}';
-				opening_tag += '${(v => v == null ? "" : ` ' + name + '="${@escape(' + snippet + ')}"`)(' + snippet + ')}';
 			} else {
 				opening_tag += ` ${attribute.name}="${stringify_attribute(attribute, true)}"`;
 			}

src/runtime/internal/ssr.ts

@@ -134,7 +134,7 @@ export function get_store_value<T>(store: Readable<T>): T | undefined {
 }
 
 export function add_attribute(name, value) {
-	if (!value) return '';
+	if (value == null) return '';
 	return ` ${name}${value === true ? '' : `=${typeof value === 'string' ? JSON.stringify(value) : `"${value}"`}`}`;
 }
 

test/runtime/samples/attribute-false/_config.js

@@ -1,5 +1,3 @@
 export default {
-	skip_if_ssr: true,
-
 	html: `<div class="false"></div>`,
 };

test/runtime/samples/attribute-null-classname-no-style/_config.js

@@ -1,6 +1,4 @@
 export default {
-	skip_if_ssr: true,
-
 	props: {
 		testName: "testClassName"
 	},

test/runtime/samples/attribute-null-classname-with-style/_config.js

@@ -1,15 +1,8 @@
 export default {
-	skip_if_ssr: true,
+	html: `<div class=" svelte-x1o6ra"></div>`,
-
-	props: {
-		testName: "testClassName"
-	},
-
-	html: `<div class="testClassName svelte-x1o6ra"></div>`,
 
 	test({ assert, component, target }) {
 		const div = target.querySelector('div');
-		assert.equal(div.className, 'testClassName svelte-x1o6ra');
 
 		component.testName = null;
 		assert.equal(div.className, ' svelte-x1o6ra');
@@ -40,5 +33,8 @@ export default {
 
 		component.testName = '';
 		assert.equal(div.className, ' svelte-x1o6ra');
+
+		component.testName = 'testClassName';
+		assert.equal(div.className, 'testClassName svelte-x1o6ra');
 	}
 };

test/runtime/samples/attribute-null-classnames-no-style/_config.js

@@ -1,6 +1,4 @@
 export default {
-	skip_if_ssr: true,
-
 	props: {
 		testName1: "test1",
 		testName2: "test2",

test/runtime/samples/attribute-null-classnames-with-style/_config.js

@@ -1,6 +1,4 @@
 export default {
-	skip_if_ssr: true,
-
 	props: {
 		testName1: "test1",
 		testName2: "test2",

test/runtime/samples/attribute-null-func-classname-no-style/_config.js

@@ -1,6 +1,4 @@
 export default {
-	skip_if_ssr: true,
-
 	props: {
 		testName: "testClassName"
 	},

test/runtime/samples/attribute-null-func-classname-with-style/_config.js

@@ -1,6 +1,4 @@
 export default {
-	skip_if_ssr: true,
-
 	props: {
 		testName: "testClassName"
 	},

test/runtime/samples/attribute-null-func-classnames-no-style/_config.js

@@ -1,6 +1,4 @@
 export default {
-	skip_if_ssr: true,
-
 	props: {
 		testName1: "test1",
 		testName2: "test2",

test/runtime/samples/attribute-null-func-classnames-with-style/_config.js

@@ -1,6 +1,4 @@
 export default {
-	skip_if_ssr: true,
-
 	props: {
 		testName1: "test1",
 		testName2: "test2",

test/runtime/samples/attribute-null/_config.js

@@ -1,5 +1,3 @@
 export default {
-	skip_if_ssr: true,
-
 	html: `<div></div>`,
 };

test/runtime/samples/attribute-undefined/_config.js

@@ -1,5 +1,3 @@
 export default {
-	skip_if_ssr: true,
-
 	html: `<div></div>`,
 };