-ReactMount._renderNewRootComponent(
nextWrappedElement, // scr:------------------> ReactElement[2]
container, // scr:------------------> document.getElementById('root')
shouldReuseMarkup, // scr: null from ReactDom.render()
nextContext, // scr: emptyObject from ReactDom.render()
)
关键词：React首次渲染的解析一（纯DOM元素）