fix(runtime-core/vnode): should not render boolean values in vnode children (close #574)

packages/runtime-core/src/vnode.ts

@@ -337,7 +337,7 @@ export function createCommentVNode(
 }
 
 export function normalizeVNode<T, U>(child: VNodeChild<T, U>): VNode<T, U> {
-  if (child == null) {
+  if (child == null || typeof child === 'boolean') {
     // empty placeholder
     return createVNode(Comment)
   } else if (isArray(child)) {
@@ -348,7 +348,7 @@ export function normalizeVNode<T, U>(child: VNodeChild<T, U>): VNode<T, U> {
     // always produce all-vnode children arrays
     return child.el === null ? child : cloneVNode(child)
   } else {
-    // primitive types
+    // strings and numbers
     return createVNode(Text, null, String(child))
   }
 }