1.学习{props.children}的用法
function ChildComponent(props){
return (
<div>
{props.children}
</div>
);
}
function ParentComponent() {
return (
<ChildComponent>
<h1>abcd</h1>
<h2>efgh</h2>
</ChildComponent>
);
}
ReactDOM.render(
<ParentComponent />,
document.getElementById('root')
);