运算

if-else

class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      isShow:true
    }
  }
  render() {
    return (
      <div>
        {this.Message()}
      </div>
    )
  }
  Message(){
    if(this.state.isShow){
      return (<span>显示</span>)
    }else{
      return (<span>隐藏</span>)
    }
  }
}
export default App;

三元

<p>{this.state.isShow?'good':'hello world'}</p>

for map

<div>{this.state.arr.map(item=>{
        return (<p>{item}</p>)
        })}</div>
</div>