react 开始 七 Key

var a=[
  {id:1,value:11},
  {id:2,value:22}]
function AAA(props)
{
  //map里直接写函数收到iterator一样的东西 然后设置element
const B = 
<div>{
  props.as.map((param)=><div key={param.id}> 
    {param.value}</div>
  )}
</div>
return( <div>{B}</div> )
}

ReactDOM.render(
  <AAA as={a} />,
  document.getElementById('example')
);