[英]Mapping ReactJS list with data from an API.graphql call
我正在嘗試將包含來自 API 調用的數據的列表映射到 DynamoDB,我承認,我自學的 JavaScript 知識存在許多漏洞。
如何將在songs = () => {}
創建的songList
對象暴露給我返回的songList.map?
我已經嘗試在組件聲明之外以及函數內外使用 API 調用。
import React, { Component } from 'react';
import * as queries from '../graphql/queries';
import Song from './Song';
API.configure(awsconfig);
class SongList extends Component {
render() {
const songs = () => {
API.graphql(graphqlOperation(queries.listSongs)).then(function (songData) {
const songList = songData['data']['listSongs']['items'];
return songList;
});
}
console.log(songs()); // undefined
return (
<div>
{
songList.map((song, i) => <Song
key={i}
title={song['title']}
author={song['author']}
keywords={song['keywords']}
instruments={song['instruments']}
isrcCode={song['isrcCode']}
lyrics={song['lyrics']}
/>)
}
</div>
)
}
}
export default SongList;
永遠不要在渲染方法中做請求
componentDidMount(){
const songs = () => {
API.graphql(graphqlOperation(queries.listSongs)).then(function (songData) {
const songList = songData['data']['listSongs']['items'];
return songList;
});
this.setState({list:sondgs()})
}
render() {
let list = this.state.list || []
return (
<div>
{
list.map((song, i) => <Song
key={i}
title={song['title']}
author={song['author']}
keywords={song['keywords']}
instruments={song['instruments']}
isrcCode={song['isrcCode']}
lyrics={song['lyrics']}
/>)
}
</div>
)
}
}
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