使用mongoose时未定义Graphql错误newUser

const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });

const mongoose = require('mongoose');

const userSchema = new mongoose.Schema({
  // 定义用户模型的字段和类型
  name: String,
  age: Number,
  // 其他字段...
});

const User = mongoose.model('User', userSchema);

module.exports = User;

const { GraphQLObjectType, GraphQLString, GraphQLInt } = require('graphql');
const User = require('./path/to/User'); // 导入User模型

const UserType = new GraphQLObjectType({
  name: 'User',
  fields: {
    name: { type: GraphQLString },
    age: { type: GraphQLInt },
    // 其他字段...
  },
});

const RootQuery = new GraphQLObjectType({
  name: 'RootQueryType',
  fields: {
    newUser: {
      type: UserType,
      args: {
        name: { type: GraphQLString },
        age: { type: GraphQLInt },
        // 其他参数...
      },
      resolve(parent, args) {
        const user = new User(args); // 创建新用户
        return user.save(); // 保存用户到数据库
      },
    },
    // 其他查询字段...
  },
});

module.exports = RootQuery;