next.js 未呈现React组件网

t98cgbkg  于 2023-03-02  发布在  React
关注(0)|答案(1)|浏览(229)

我的组件是beign渲染空白在结束一切都很好的api调用,我添加了一些console. log()调试,谁能给我一个提示?
基本上,我希望从具有以下JSON结构的api中检索数据

[
    {
        "trackName": "Beira de Piscina (Remix)",
        "trackUri": "spotify:track:6a0kQTjyGmfwBF0tLVgEha",
        "artistImage": "https://i.scdn.co/image/ab67616d0000b27366127aa6c868a01e97f62d64"
    },
    {
        "trackName": "Beira de Piscina",
        "trackUri": "spotify:track:25XUxLporfgzl2rf2mtgmj",
        "artistImage": "https://i.scdn.co/image/ab67616d0000b2738e2cc04d7c1ed2beb3216ff2"
    }
]

我想在一个页面上呈现这些,这是一个示例代码,但我不明白为什么我得到一个空白页面:(
这是我的准则

import {useState} from "react";

export default function SearchTracks() {

    const [formSuccess, setFormSuccess] = useState(false)
    const [trackList, setTracklist] = useState()

    const handleSubmit = async (event: any) => {
        event.preventDefault()

        const data = {
            trackName: event.target.trackName.value
        }

        const endpoint = `http://myEndPoint:8080/tracks?trackName=${data.trackName}`
        const options = {
            method: 'GET',
            headers: {
                'access-token': 'MyAccessToken'
            }
        }
        const response = await fetch(endpoint, options)

        const result = await response.json()
        setFormSuccess(true)

        setTracklist(result)
    };

    const renderTrack = (trackListResponse) : any => {
        const myMap = new Map(Object.entries(trackListResponse))
        return myMap.forEach((trackValue) => {
            return trackValue.map(track => {
                let value = buildTrackContainer(track)
                console.log(value)
                return value
            })
        })
    }

    const buildTrackContainer = (track) => {
       console.log("Building track: " + track.trackName)
       return <li key={track.trackUri}>
            <p>{track.trackName}</p>
            <p>{track.trackUri}</p>
            <img src={track.artistImage}/>
        </li>
    }

    return (
        <div>
            {formSuccess ?
                <ul>
                    { renderTrack({trackList}) }
                </ul>
                :
                <form onSubmit={handleSubmit}>
                    <label htmlFor="trackName">Track Name</label>
                    <input type="text" id="trackName" name="trackName" required/>
                    <button type="submit">Submit</button>
                </form>
            }
        </div>
    )
}

在控制台中,我可以看到react元素在函数中返回
My Console Logs
Result Page

5tmbdcev

5tmbdcev1#

问题出在您的renderTrack()函数中。请尝试以下操作:

const renderTrack = (trackListResponse) : any => {
        return trackListResponse.trackList.map(track =>
            buildTrackContainer(track)
        );
    };

问题是forEach实际上并不返回任何东西,所以它得到的只是undefined。另一种方法是创建一个空数组,这将在forEach调用中将元素推入空数组,但这感觉可能比它的价值更麻烦。例如:

const renderTrack = (trackListResponse) : any => {
        const myMap = new Map(Object.entries(trackListResponse));
        const renderElements = [];
        myMap.forEach(trackValue => {
            return trackValue.map(track => {
                let value = buildTrackContainer(track);
                renderElements.push(value);
            });
        });
        return renderElements;
    };

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