useEffect 被執(zhí)行兩次
import React, { useState, useEffect } from "react";
export default function StateFunction() {
? const [num, setNum] = useState(1);
? useEffect(() => {
? ? console.log("@");
? });
? return <div>這是一個函數(shù)組件 - {num}</div>;
}
// 然后每次刷新,? @都會被打印兩次
2022-05-09
就算加上 [] 還是會被執(zhí)行兩次
import React, { useState, useEffect } from "react";
export default function StateFunction() {
? const [num, setNum] = useState(1);
? useEffect(() => {
? ? console.log("@");
? }, []);
? return <div>這是一個函數(shù)組件 - {num}</div>;
}