react定义组件

1。函数式组件

      //函数式组件
 function Hello() {
    return (
      <div className="pname">hello word</div> 
          )
 }

2.类组件

    //类组件
class Hello extends React.Component{
    render(){
        return <div className="pname">hello word</div>
    }
}

3.组合组件

//组合组件
function Word(props) {
    return <div className="pname">hello,{props.name}</div>
}


class Hello extends React.Component {
    render() {
        return (
            <div>
                <Word name="word1" />
                <Word name="word2" />
                <Word name="word3" />
            </div>
        )
    }
}