[英]How to stop the javascript loader when the data retrieved from the database
[英]How to stop data being retrieved when my component is loaded
我只希望在單擊生成笑話(單擊此處獲取笑聲)按鈕后顯示數據,但是一旦頁面加載就會檢索數據。 我該如何阻止呢?
`import React, { useState, useEffect } from "react";
function App() {
const [joke, getJoke] = useState(" ")
const newJoke = () => {
fetch("http://api.icndb.com/jokes/random")
.then(result => result.json())
.then(result2 => {
console.log(result2)
getJoke(result2.value.joke)
})
}
useEffect(() => {
newJoke()
}, [])
return (
<div className="jokeSection">
<h1>Chuck norris jokes</h1>
<h3>{joke}</h3>
<button onClick={() => newJoke()}>Click here for a chuckle</button>
</div>
)
}
export default App;`
這是一種好的編碼方式嗎? 我應該使用不同的功能,例如 componentDidMount 嗎?
`import React, { useState, useEffect } from "react";
function App() {
const [joke, getJoke] = useState(" ")
const newJoke = () => {
fetch("http://api.icndb.com/jokes/random")
.then(result => result.json())
.then(result2 => {
console.log(result2)
getJoke(result2.value.joke)
})
}
useEffect(() => {
}, [])
return (
<div className="jokeSection">
<h1>Chuck norris jokes</h1>
<h3>{joke}</h3>
<button onClick={() => newJoke()}>Click here for a chuckle</button>
</div>
)
}
export default App;`
將它從 useEffect 中刪除並保持 onClick 並且應該這樣做。如評論中所述,useEffect 將在每次頁面加載時運行。
我寧願為笑話切換和笑話數據保持 2 種狀態,如下所示。
名為 useEffect 的效果掛鈎用於使用 axios 從 API 獲取數據,並使用狀態掛鈎的更新功能在組件的本地狀態中設置數據。 承諾解決發生在 async/await 中。
import React, { useState, useEffect } from "react";
import ReactDOM from "react-dom";
import axios from "axios";
function App() {
const [joke, setJoke] = useState(0);
const [jokeData, setJokeData] = useState("");
function newJoke(){
setJoke(joke=>joke+1);
}
useEffect( () => {
(async function loadJoke() {
if(joke>0){
const response=await axios.get('https://api.icndb.com/jokes/random');
setJokeData(response.data.value.joke);
}
})();
}, [joke]);
return (
<div className="jokeSection">
<h1>Chuck norris jokes</h1>
<h3>{jokeData}</h3>
<button onClick={() => newJoke()}>Click here for a chuckle</button>
</div>
);
}
export default App;
const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.