150. Virtual DOM V - JSX 2

This is a follow-up on 143. Virtual DOM IV - JSX 1.

Congratulations on your pass on problem 143!

Now in this problem, please modify your code to support following.

1. nesting elements

<p><i>BFE.dev</i> is <b>cool</b>!</p>

This means JSXChild needs to support JSXElement as well.

JSXChild:   JSXText+  JSXElement

2. Functional Component

As a convention, intrinsic HTML tags are lower cases and Functional Components have capitalized initials.

const Heading =   ({children, ...res}) => h('h1', res, ...children)  <Heading>BFE.<i>dev</i></Heading>

If your code in problem 143 already supports this, that's fantastic 👍! Just copy your code here and hope it shall pass.