我正在开发一个 MERNG 应用程序，到目前为止一切都运行良好，但我在 useMutations 的前端遇到了一些错误，让我向您解释一下。

因此，在登录/注册部分，如果您将字段留空或在登录中，如果在数据库中找不到您的用户，它会出现错误，并且我在函数 onError(err) 中收到这些错误，但是，问题是，它总是给我错误，它说，无法读取未定义的属性“扩展”，即使我没有错误，它也会给出错误，让我给你展示代码

import React, { useState } from "react";
import { useMutation, gql } from "@apollo/client";

import { useHistory } from "react-router-dom";
import { useDispatch } from "react-redux";

import {
  FormAuth,
  TitleAuth,
  TitleAuthImage,
  ContainInput,
  InputAuth,
  ContainSingleInput,
  ContainButtons,
  Button,
  ButtonSpan
} from "../../website/Auth/AuthStyled";

import instagram from "../../img/instagram.svg";
import Loading from "../Loading/Loading";

const Login = ({ setLogin }) => {
  const history = useHistory();
  const dispatch = useDispatch();

  const [userData, setUserData] = useState({
    email: "",
    password: ""
  });

  const [errors, setErrors] = useState({});

  const [addUser, { loading }] = useMutation(LOGIN_MUTATION, {
    update(
      _,
      {
        data: { login: data }
      }
    ) {
      dispatch({ type: "LOGIN", payload: data });
      history.push(`/profile/${data.id}`);
    },
    onError(err) {
      setErrors(err.graphQLErrors[0].extensions.exception.errors);
    },
    variables: userData
  });

  const handleSubmit = e => {
    e.preventDefault();
    addUser();
    setUserData({ email: "", password: "" });
  };

  // Framer motion animations

  const PopUp = {
    hidden: { x: 1000 },
    visible: {
      x: 0,
      transition: { duration: 0.7 }
    }
  };

  return (
    <>
      {!loading ? (
        <FormAuth
          onSubmit={handleSubmit}
          variants={PopUp}
          initial="hidden"
          animate="visible"
        >
          <TitleAuth>
            <TitleAuthImage src={instagram} />
          </TitleAuth>

          <ContainInput>
            <ContainSingleInput top="2rem">
              <InputAuth
                name="email"
                type="email"
                placeholder={errors.email ? errors.email : "Email"}
                maxLength="50"
                value={userData.email}
                onChange={e =>
                  setUserData({ ...userData, email: e.target.value })
                }
              />
            </ContainSingleInput>
            <ContainSingleInput top="7rem">
              <InputAuth
                name="password"
                type="password"
                placeholder={errors.password ? errors.password : "Password"}
                maxLength="50"
                value={userData.password}
                onChange={e =>
                  setUserData({ ...userData, password: e.target.value })
                }
              />
            </ContainSingleInput>
          </ContainInput>

          <ContainButtons>
            <Button
              type="submit"
              Login
              whileHover={{ scale: 1.1 }}
              whileTap={{ scale: 0.85 }}
            >
              Login
            </Button>
            <ButtonSpan
              Register
              whileHover={{ scale: 1.1 }}
              whileTap={{ scale: 0.85 }}
              onClick={() => setLogin(false)}
            >
              Register
            </ButtonSpan>
          </ContainButtons>
        </FormAuth>
      ) : (
        <Loading />
      )}
    </>
  );
};

const LOGIN_MUTATION = gql`
  mutation login($email: String!, $password: String!) {
    login(email: $email, password: $password) {
      id
      email
      password
      token
    }
  }
`;

export default Login;

这是登录的样子，那里的凭据是正确的

单击登录后浏览器中的错误

这里奇怪的是，它之前正常工作，但知道它坏了，我不知道为什么或如何，如果我遇到错误，它们将出现在输入的占位符中，但知道，它总是坏掉