提供对未定义的检查
prop.data，然后渲染该组件，因为道具最初可能不提供数据，但在第二个渲染中可用。那应该解决你的问题
class App extends React.Component { render() { var data = [{"transid":3426,"acct":"acct1","category":"Auto"}, {"transid":3427,"acct":"acct2","category":"Subscriptions"}] return ( <div ><TransactionManagerView data={data}/></div> ) }}const TransactionManagerView = function(props) { console.log(props.data); return ( <ul> { props.data && props.data.map(function(el,index) {return <li key={index}>{el.category}</li> }) } </ul> )}ReactDOM.render(<App/>, document.getElementById('app'));<script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.14.8/react.min.js"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.14.8/react-dom.min.js"></script><div id="app"></div>
