我有一个计数器和一个console.log()来useEffect记录我状态中的每个变化,但是useEffect在挂载时被调用两次。我正在使用 React 18。这是我项目的CodeSandbox和以下代码:
import { useState, useEffect } from "react";
const Counter = () => {
const [count, setCount] = useState(5);
useEffect(() => {
console.log("rendered", count);
}, [count]);
return (
<div>
<h1> Counter </h1>
<div> {count} </div>
<button onClick={() => setCount(count + 1)}> click to increase </button>
</div>
);
};
export default Counter;
Run Code Online (Sandbox Code Playgroud)