React JS中的未定义对象 [英] Undefined object in react js

问题描述

我遇到以下错误:

Uncaught ReferenceError: videos2 is not defined

在此应用中:

class App extends Component {
constructor(props) {
    super(props)

    this.state = {
        videos2:[],
        selectedVideo:null
    }

    this.DMSearch()
}

    DMSearch(){
        fetch("https://api.dailymotion.com/videos?fields=description,id,thumbnail_url,title,&limit=5&search=cars")
        .then(response => response.json())
        .then(data=>this.setState({
            videos2:data.videos2, 
            selectedVideo:videos2[0]}))
        console.log(videos2)
    }
    render () {
        const {videos2}=this.state
        return (
            <div>
                <SearchBar onSearchTermChange= {DMSearch}/>
                <VideoDetail video={this.state.selectedVideo}/> 
                <VideoList 
                onVideoSelect={selectedVideo=>this.setState({selectedVideo})}
                videos2={this.state.videos2}/>
            </div>
        )
    }
}  

因此，我想知道我应该在哪里定义video2，而不是已经定义的地方.任何人都可以指出可能导致该错误的组件部分吗?

Therefore Im wondering where should I define videos2 apart from where it is defined already. Anyone could point me out to the part of the component that might be causing the error?

实际上，它与api json的成形方式有关. 这是从json获取列表的正确方法:

Actually it had to do with the way api json was shaped. This is the proper way to fetch the list from json:

this.setState({
               videos2: videos2.list, 
               selectedVideo: videos2[0]
            });

推荐答案

在DMSearch中，videos2未定义.

In DMSearch, videos2 is undefined.

DMSearch() {
  fetch("https://api.dailymotion.com/videos?fields=description,id,thumbnail_url,title,&limit=5&search=cars")
    .then(response => response.json())
    .then(data => {
      let videos2 = data.videos2; //define it here

      this.setState({
        videos2: videos2,
        selectedVideo: videos2[0] // <-- this line will throw error
      })
    })
  console.log(videos2) // <-- and this too
}

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