Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
3.9k views
in Technique[技术] by (71.8m points)

reactjs - how to use a specific index of a array in reducer

want to take a specific data in reducer . I got an error which says

TypeError: Cannot read property 'data' of undefined

I'm calling the action at useEffect with a empty array dependency

  useEffect(() => {
    props.getOrderDetails(props.match.params.guid)
  }, [])

here's where I'm trying to use it

<div>
 {props.orderDetails[0].data}
  </div>

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

So I think what you are asking is why you can use it some places and not... Remember Redux is the simple source of truth. So. It is getting rendered first before for component mounts, so in the useEffect() you can use setState, useState and make the 'props.orderDetails.data' a state variable. that should fix the problem because it will execute AFTER the component mounts.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...