GraphQL Mutation addUser无法创建用户问题排查求助

问题根因与修复方案 #

你遇到的请求未进入resolver等问题全部由以下可复现的语法/逻辑错误导致，按优先级修复即可：

1. resolvers.js 结构错误（核心原因，直接导致Mutation未注册） #

你当前的Mutation配置块写在了resolvers对象的闭合大括号外面，属于未挂载的无效代码，GraphQL服务根本识别不到addUser resolver。
修复方案：把整个Mutation块移到resolvers对象内部：

const { User, Book } = require("../models");
const { AuthenticationError } = require("apollo-server-express");
const { signToken } = require("../utils/auth");

const resolvers = {
  Query: {
    me: async (parent, args, context) => {
      if (context.user) {
        return User.findOne({ _id: context.user._id }).populate("books");
      }
      throw new AuthenticationError("You need to log in");
    },
  },
  // Mutation块移到resolvers对象内部
  Mutation: {
    addUser: async (parent, args) => {
      // 先解构args获取参数，否则username等变量未定义
      const { username, email, password } = args;
      console.log("resolver test", args);
      const user = await User.create({ username, email, password });
      const token = signToken(user);
      return { token, user };
    },

    login: async (parent, { email, password }) => {
      // 给User.findOne加await
      const user = await User.findOne({ email });
      if (!user) {
        throw new AuthenticationError("Invalid Login Credentials");
      }
      // 把不存在的profile变量改为user
      const correctPw = await user.isCorrectPassword(password);
      if (!correctPw) {
        throw new AuthenticationError("Invalid Login Credentials");
      }
      const token = signToken(user);
      return { token, user };
    },

    saveBook: async (parent, { bookData }, context) => {
      if (context.user) {
        return User.findOneAndUpdate(
          { _id: context.user._id },
          { $addToSet: { savedBooks: bookData } },
          { new: true }
        );
      }
      throw new AuthenticationError("You need to log in");
    },

    deleteBook: async (parent, { bookId }, context) => {
      if (context.user) {
        return User.findOneAndUpdate(
          // 修正拼写错误contex→context
          { _id: context.user._id },
          // 修正取值错误context.bookId→传入的bookId参数
          { $pull: { savedBooks: { bookId: bookId } } },
          { new: true }
        );
      }
      throw new AuthenticationError("You need to log in");
    },
  }
};
module.exports = resolvers;

2. 前端SignupForm.js 逻辑错误 #

Apollo Client的useMutation返回的结果不是原生Fetch的Response对象，没有ok属性，也不需要调用json()方法，返回数据直接挂载在data字段下：

const handleFormSubmit = async (event) => {
  event.preventDefault();

  const form = event.currentTarget;
  if (form.checkValidity() === false) {
    event.preventDefault();
    event.stopPropagation();
  }

  try {
    const { data } = await addUser({
      variables: { ...userFormData },
    });
    const { token, user } = data.addUser;
    console.log(user);
    Auth.login(token);
  } catch (err) {
    console.error(err);
    setShowAlert(true);
  }

  setUserFormData({
    username: "",
    email: "",
    password: "",
  });
};

3. auth.js 中间件错误 #

中间件catch块引用了不存在的res变量，Apollo上下文中间件不需要返回响应，直接返回req即可：

authMiddleware: function ({ req }) {
  let token = req.query.token || req.headers.authorization || req.body.token;

  if (req.headers.authorization) {
    token = token.split(" ").pop().trim();
  }

  if (!token) {
    return req;
  }

  try {
    const { data } = jwt.verify(token, secret, { maxAge: expiration });
    req.user = data;
  } catch {
    console.log("Invalid token");
    // 删除不存在的res返回逻辑
  }

  return req;
},

以上错误全部修复后，addUser Mutation即可正常触发，返回token完成自动登录。

内容的提问来源于stack exchange，提问作者Leland Cypress