NextJS从另一个组件访问变量

Question

我在组件中有一个变量。我想要函数SetScore()

返回的变量值btnRotate.jsx

setScoreState((prevS) => {
if (btn.deg == deg) {


//console.log(prevS);
return prevS + 1;
} else {

//console.log(prevS);
return prevS;
}
});

我想在这里使用变量pres的值

Img.jsx

function Img({ i, lengthArr }) {
const [width, setWidth] = useState(0);
const [score1, setScore1] = useState(0);
const [score2, setScore2] = useState(0);
///
const [scoreState, setScoreState] = useState(1);
//console.log(prevS);

...

Answer 1

您可以使用useRef来保持先前的状态值

import { useRef, useState } from 'react'
function Img({ i, lengthArr }) {
const [width, setWidth] = useState(0);
const [score1, setScore1] = useState(0);
const [score2, setScore2] = useState(0);
const [scoreState, setScoreState] = useState(1);
const scoreStateRef = useRef(1); //add `useRef`

console.log(scoreStateRef.current); //replace for `prevS`

...

下面是如何设置scoreStateRef 的值

setScoreState((prevS) => {
scoreStateRef.current = prevS; //set value here
if (btn.deg == deg) {
//console.log(prevS);
return prevS + 1;
} else {
//console.log(prevS);
return prevS;
}
});