use value property for textareas

src/generators/dom/visitors/Element/lookup.ts

@@ -109,7 +109,7 @@ const lookup = {
 	title: {},
 	type: { appliesTo: [ 'button', 'input', 'command', 'embed', 'object', 'script', 'source', 'style', 'menu' ] },
 	usemap: { propertyName: 'useMap', appliesTo: [ 'img', 'input', 'object' ] },
-	value: { appliesTo: [ 'button', 'option', 'input', 'li', 'meter', 'progress', 'param', 'select' ] },
+	value: { appliesTo: [ 'button', 'option', 'input', 'li', 'meter', 'progress', 'param', 'select', 'textarea' ] },
 	width: { appliesTo: [ 'canvas', 'embed', 'iframe', 'img', 'input', 'object', 'video' ] },
 	wrap: { appliesTo: [ 'textarea' ] }
 };

test/runtime/samples/textarea-value/_config.js

@@ -0,0 +1,17 @@
+export default {
+	'skip-ssr': true, // SSR behaviour is awkwardly different
+
+	data: {
+		foo: 42
+	},
+
+	html: `<textarea></textarea>`,
+
+	test ( assert, component, target ) {
+		const textarea = target.querySelector( 'textarea' );
+		assert.strictEqual( textarea.value, '42' );
+
+		component.set({ foo: 43 });
+		assert.strictEqual( textarea.value, '43' );
+	}
+};

test/runtime/samples/textarea-value/main.html

@@ -0,0 +1 @@
+<textarea value='{{foo}}'/>