当我进入FormPage时，我调用这个customHook来获取我可能在表单调查中上传的图像的路径。但是在一开始我得到'image/event/NaN'，几毫秒后它变成了'image/event/5'

import { ref, listAll } from "firebase/storage";
import { FirebaseStorage } from "../firebase/config";
import { useEffect, useState } from "react";

export const useGetLastFolder = (postType) => {

    const [folderPath, setFolderPath] = useState([]);

    const listRef = ref(FirebaseStorage, `image/${postType}`);

    useEffect(() => {
        listAll(listRef)
            .then((res) => {
                const arrayFolders = res.prefixes.map((folderRef) => {
                    return folderRef.name;
                })
                const lastFolder = (parseInt(arrayFolders[arrayFolders.length - 1]) + 1).toString();
                setFolderPath(`image/${postType}/${lastFolder}`);
            })
            .catch((error) => {
                // Uh-oh, an error occurred!
            });

    }, [])

    return {
        lastPossibleFolderPath: folderPath
    }

}

我测试了putting as initialState '[4]'，我得到了'image/event/5'，它工作得很好。
因此setFolders设置undefined（？）第一次渲染，然后设置文件夹数组。