如何在React中显示json中的数据

Question

我尝试创建一个简单的应用程序，生成随机报价。我创建了一个函数(我认为)从json文件中获得我想要的数据。但是当我试图将该函数传递给我的应用程序函数时，我得到错误:对象作为React子对象无效(found: [object Promise])

函数引用:

function Quote (data) {
var x = (Math.floor(Math.random() * (103 - 1) + 1) );
return fetch('https://gist.githubusercontent.com/camperbot/5a022b72e96c4c9585c32bf6a75f62d9/raw/e3c6895ce42069f0ee7e991229064f167fe8ccdc/quotes.json')
.then((response) => response.json())
.then((responseJson) => {
console.log(responseJson['quotes'][0]['author']);
return responseJson['quotes'][x]['author'];
})


.catch((error) => {
console.error(error);
});
}

应用功能:

function App() {
var text = '';
return (

<div id="quote-box">
<div id="author"><Quote /></div>
<button id="new-quote">New Quote</button>
<a href="twitter.com" id="tweet-quote">Tweet</a>
</div>
);
}

Answer 1

我将使用useEffect在开始时触发调用。并使用useState保存该值。然后也将相同的逻辑添加到onClick。

import { useEffect, useState } from "react";
function getQuote() {
var x = Math.floor(Math.random() * (103 - 1) + 1);
return fetch(
"https://gist.githubusercontent.com/camperbot/5a022b72e96c4c9585c32bf6a75f62d9/raw/e3c6895ce42069f0ee7e991229064f167fe8ccdc/quotes.json"
)
.then((response) => response.json())
.then((responseJson) => {
console.log(responseJson["quotes"][0]["author"]);
return responseJson["quotes"][x]["author"];
})
.catch((error) => {
console.error(error);
});
}
export default function App() {
const [author, setAuthor] = useState("");
useEffect(() => {
getQuote().then((newAuthor) => setAuthor(newAuthor));
}, []);
return (
<div id="quote-box">
<div id="author">{author}</div>
<button
id="new-quote"
onClick={() => getQuote().then((newAuthor) => setAuthor(newAuthor))}
>
New Quote
</button>
<a href="twitter.com" id="tweet-quote">
Tweet
</a>
</div>
)
}

Answer 2

您也可以用这种方式存档。创建一个自定义钩子并使用它

import React from "react";
function useFetchQuote(newQuote) {
const [author, setAuthor] = React.useState();
React.useEffect(() => {
var x = Math.floor(Math.random() * (20 - 1) + 1);
return fetch(
"https://gist.githubusercontent.com/camperbot/5a022b72e96c4c9585c32bf6a75f62d9/raw/e3c6895ce42069f0ee7e991229064f167fe8ccdc/quotes.json"
)
.then((response) => response.json())
.then((responseJson) => {
console.log(responseJson["quotes"][x]["author"]);
setAuthor(responseJson["quotes"][x]["author"]);
})
.catch((error) => {
console.error(error);
});
}, [newQuote]);
return { author };
}
function App() {
const [newQuote, setQuote] = React.useState(0);
const { author } = useFetchQuote(newQuote);
return (
<div id="quote-box">
<div id="author">{author}</div>
<button id="new-quote" onClick={() => setQuote(newQuote + 1)}>
New Quote
</button>
<a href="twitter.com" id="tweet-quote">
Tweet
</a>
</div>
);
}
export default App;

Answer 3

在React组件中返回承诺将不像您在代码中所做的那样工作。React组件必须返回一个jsx。例如，在名为Quote.js

的文件中

import * as React from 'react';
const url =
'https://gist.githubusercontent.com/camperbot/5a022b72e96c4c9585c32bf6a75f62d9/raw/e3c6895ce42069f0ee7e991229064f167fe8ccdc/quotes.json';
const Qoute = () => {
const [quote, setQuote] = React.useState(null);
React.useEffect(() => {
fetch(url)
.then((response) => response.json())
.then((data) => {
const randomNumber = 1; // Generate random number which is lesser or equal to data's length
setQuote(data['quotes'][randomNumber]);
});
}, []);
if (!quote) return <React.Fragment>Loading...</React.Fragment>;
return <div>{JSON.stringify(quote)}</div>;
};
export default Qoute;

然后你只需要将它导入到你想要使用它的地方并像这样调用它

<Quote />

PS:我从typescript转换这个，如果有些东西不工作，我会很乐意帮助。请记得更新行我在那里发表评论。古德勒克,兄弟。