Cannot read properties of undefined (reading 'map')

제로초님, 코드를 따라친 후에 로그아웃을 하고 다시 로그인 하면 이런 에러메세지가 뜹니다.

그런데 네트워크 탭을 보면 로그인이 정상적으로 된거 같아서 새로고침을 하면 에러 메세지가 사라지고 슬랙에서 로그인된 화면이 제대로 뜹니다.

근데 또 여기서 워크스페이스를 생성하려고 하면 콘솔에 axioserror메세지가 떠서 어떻게 해야될지 모르겠습니다..

Workspace/index.tsx

import axios from "axios";
import React, { FC, useCallback, useState } from "react";
import useSWR from 'swr';
import fetcher from "@utils/fetcher";
import { Navigate, Routes, Route } from "react-router-dom";
import { AddButton, Channels, Chats, Header, LogOutButton, MenuScroll, ProfileImg, ProfileModal, RightMenu, WorkspaceButton, WorkspaceName, Workspaces, WorkspaceWrapper } from "@layouts/Workspace/style";
import gravatar from 'gravatar';
import loadable from '@loadable/component';
import Menu from "../../components/Menu";
import Modal from "../../components/Modal";
import { Link } from "react-router-dom";
import { IUser } from "@typings/db";
import { Button, Input, Label } from "@pages/SignUp/styles";
import useInput from "@hooks/useInput";
import {toast} from 'react-toastify';
const Channel = loadable(() => import('@pages/Channel')); 
const DirectMessage = loadable(() => import('@pages/DirectMessage'));

const Workspace: FC<React.PropsWithChildren<{}>> = ({children}) => {
  const [showUserMenu, setShowUserMenu] = useState(false);
  const [showCreateWorkspaceModal, setShowCreateWorkspaceModal] = useState(false);
  const [newWorkspace, onChangeNewWorkspace, setNewWorkspace] = useInput('');
  const [newUrl, onChangeNewUrl, setNewUrl] = useInput('');
  // revalidate = 서버로 요청 다시 보내서 데이터를 다시 가져옴
  // mutate = 서버에 요청 안보내고 데이터를 수정
  const {data: userData, error, mutate} = useSWR<IUser | false>('/api/users', fetcher, {
    dedupingInterval: 2000,
  });

  const onLogout = useCallback(() => {
    axios.post('/api/users/logout', null , {
      withCredentials: true,
    })
    .then(() => {
      mutate(false, false);
    })
  }, []);

  const onClickUserProfile = useCallback((e: any) => {
    e.stopPropagation();
    setShowUserMenu((prev) => !prev);
  }, [])

  const onClickCreateWorkspace = useCallback(() => {
    setShowCreateWorkspaceModal(true);
  }, [])

  const onCreateWorkspace = useCallback((e: any) => {
    e.preventDefault();
    // 띄어쓰기도 검사해줘야됨
    if(!newWorkspace || !newWorkspace.trim()) return;
    if(!newUrl || !newUrl.trim()) return;
    axios.post('http://localhost:3095/api/workspaces', {
      workspace: newWorkspace,
      url: newUrl,
    }, {
      withCredentials: true,
    })
    .then(() => {
      mutate();
      setShowCreateWorkspaceModal(false);
      setNewWorkspace('');
      setNewUrl('');
    })
    .catch((error) => {
      console.dir(error);
      // 에러가 나면 사용자가 인지하게 해줌
      toast.error(error.response?.data, { position: 'bottom-center' })
    })
  }, [newWorkspace, newUrl])

  const onCloseModal = useCallback(() => {
    setShowCreateWorkspaceModal(false);
  }, [])

  if(!userData) {
    return <Navigate to="/login" />
  }

  if(!userData) return null;

  return(
    <div>
      <Header>
        <RightMenu>
          <span onClick={onClickUserProfile}>
            <ProfileImg src={gravatar.url(userData.email, { s: '28px', d: 'retro' })} alt={userData.nickname} />
            {showUserMenu && <Menu style={{ right: 0, top: 38 }} show={showUserMenu} onCloseModal={onClickUserProfile}>
              <ProfileModal>
                <img src={gravatar.url(userData.nickname, { s: '36px', d: 'retro' })} alt={userData.nickname} />
                <div>
                  <span id="profile-name">{userData.nickname}</span>
                  <span id="profile-active">Active</span>
                </div>
              </ProfileModal>
              <LogOutButton onClick={onLogout}>로그아웃</LogOutButton>
            </Menu>}
          </span>
        </RightMenu>
      </Header>
      <WorkspaceWrapper>
        <Workspaces>
          {userData?.Workspaces.map((ws) => {
            return (
              <Link key={ws.id} to={`/workspace/${123}/channel/일반`}>
                <WorkspaceButton>{ws.name.slice(0, 1).toUpperCase()}</WorkspaceButton>
              </Link>
            );
          })}
          <AddButton onClick={onClickCreateWorkspace}>+</AddButton>
        </Workspaces>
        <Channels>
          <WorkspaceName>Sleact</WorkspaceName>
          <MenuScroll>menu scroll</MenuScroll>
        </Channels>
        <Chats>
          <Routes>
            <Route path="/channel" element={<Channel />} />
            <Route path="/dm" element={<DirectMessage />} />
          </Routes>
        </Chats>
        {/* Input이 들어있으면 별도의 컴포넌트로 빼는 것을 추천(input에 글자를 입력할 때마다 여기 있는 함수들이 다 리렌더링 되기 때문에 비효율적) */}
      </WorkspaceWrapper>
      <Modal show={showCreateWorkspaceModal} onCloseModal={onCloseModal}>
        <form onSubmit={onCreateWorkspace}>
          <Label id="workspace-label">
            <span>워크스페이스 이름</span>
            <Input id="workspace" value={newWorkspace} onChange={onChangeNewWorkspace} />
          </Label>
          <Label id="workspace-url-label">
            <span>워크스페이스 이름</span>
            <Input id="workspace" value={newUrl} onChange={onChangeNewUrl} />
          </Label>
          <Button type="submit">생성하기</Button>
        </form>
      </Modal>
    </div>
  )
}

export default Workspace;

Modal/index.tsx

import React, { useCallback, FC } from "react";
import { CloseModalButton, CreateModal } from "./style";

interface Props {
  show: boolean;
  onCloseModal: () => void;
  children: React.ReactNode;
}

const Modal: FC<Props> = ({show, children, onCloseModal}) => {
  const stopPropagation = useCallback((e: any) => {
    e.stopPropagation()
  }, []);

  if(!show){
    return null;
  }
  return(
    <CreateModal onClick={onCloseModal}>
      <div onClick={stopPropagation}>
        <CloseModalButton onClick={onCloseModal}>&times;</CloseModalButton>
        {children}
      </div>
    </CreateModal>
  );
};

export default Modal;

swr2.0 버전, react v18, typescript v18

swr을 최신버전 사용해서 revalidate대신 mutate를 사용했는데 제가 잘못 사용한건지 모르겠습니다.

        <Workspaces>
          {userData.Workspaces !== undefined
          ?userData?.Workspaces.map((ws) => {
            return (
              <Link key={ws.id} to={`/workspace/${123}/channel`}>
                <WorkspaceButton>{ws.name.slice(0, 1).toUpperCase()}</WorkspaceButton>
              </Link>
            )
          })
          : null
        }
          <AddButton onClick={onClickCreateWorkspace}>+</AddButton>
        </Workspaces>