我正在使用react来呈现 json 中嵌套的属性中的数据。我在渲染未嵌套的属性(例如'name'
和'id'
时遇到问题,但是当涉及到抓取place:location{...}
等嵌套道具时,说"TypeError: Cannot read property 'location' of undefined"
我的json格式如下:
data = [ {
"end_time": "2015-03-28T21:00:00-0700",
"name": "Brkn Intl. Bay Area Season 2!",
"place": {
"name": "MVMNT Studio",
"location": {
"city": "Berkeley",
"country": "United States",
"latitude": 37.85381,
"longitude": -122.27875,
"state": "CA",
"street": "2973 Sacramento St",
"zip": "94702"
},
"id": "459771574082879"
},
"start_time": "2015-03-28T15:00:00-0700" }, ...]
这是我的反应代码:
class ResultBox extends Component {
constructor(props){
super(props);
this.state = {
posts: []
};
}
componentDidMount() {
axios.get('http://localhost:3001/api/events')
.then(res => {
let posts = res.data.map(obj => obj);
this.setState({posts});
console.log(posts);
});
}
render() {
return (
this.state.posts.map(function(events){
return <div className='result_box'>
<p>{events.name}</p>
<p>{events.place.location.city}</p> <----- This give me error!!!
</div>
})
);
}
}
任何帮助将不胜感激!!!!
答案 0 :(得分:3)
看起来并非所有events
都定义了属性place
。
您可以在每个组件上对其进行警告,也可以忽略并阻止呈现undefined
值:
this.state.posts.map(events =>
<div key={events.id} className='result_box'>
<p>{events.name}</p>
{events.place && <p>{events.place.location.city}</p>}
</div>
)
Lodash的get方法也可以为您提供帮助:
<p>{get(events, 'place.location.city', '')}</p>