Express 带有Graphql错误的节点/表达式“_author2.default不是构造函数；

我一直在寻找这个错误，但没有找到成功的解决方案。我正在学习graphql，所以我构建了一个小应用程序，下面是我的package.json：

"dependencies": {
    "apollo-server-express": "^1.3.6",
    "babel-watch": "^2.0.7",
    "body-parser": "^1.18.3",
    "express": "^4.16.3",
    "graphql": "^0.13.2",
    "graphql-tools": "^3.0.2",
    "mongoose": "^5.1.3",
    "node-uuid": "^1.4.8"
  },
  "devDependencies": {
    "babel-cli": "^6.26.0",
    "babel-preset-env": "^1.7.0"
  }

My schema.js：

import { makeExecutableSchema, addMockFunctionsToSchema } from 'graphql-tools'
import resolvers from './resolvers'

const typeDefs = `
    type Author {
        id: String
        name: String
        age: Int
        books: [String]
    }

    type Query {
        authors: [Author]
        author(id: String): Author
    }

    type Mutation {
        addAuthor(name: String!, age: Int!, books: [String]!):Author
    }
`
const schema = makeExecutableSchema({typeDefs, resolvers});

export default schema;

My Resolver.js：

import mongoose from 'mongoose';
import authorModel from './model/author';

const resolvers = {
    Query: {
        authors: () => {
            //return fakeData;
        },
        // root is never used, and args holds our filter params
        author: (root, args) => {
            //const id = args.id;
            //return fakeData.find((author) => author.id === id);
        }
    },
    // mutations changes the data states
    Mutation: {
        addAuthor: (root, {name, age, books}) => {
            console.log(name, age, books);
            const author = new authorModel({name: name, age: age, books: books});
            return author.save();
        }
    }
};

export default resolvers;

最后，我的模型author.js：

import mongoose from 'mongoose';
// to generate our unique IDs
import uuid from 'node-uuid';
const schema = mongoose.Schema;

// this schema must be compatible with schema from graphQl
const authorSchema = new schema({
    id: {type: String, default: uuid.v1},
    name: String,
    age: Number,
    books: [String]
});

export default authorSchema;

All works ok，my express与apollo server express配合使用正常，当我使用addAuthor变体时，会调用resolver中的函数addAuthor，但在创建author对象模型时发生错误，错误为：

TypeError: _author2.default is not a constructor
    at addAuthor (/home/desinv04/estudos/graphql/worldcup-graphql/resolvers.js:46:28)
    at resolveFieldValueOrError (/home/desinv04/estudos/graphql/worldcup-graphql/node_modules/graphql/execution/execute.js:531:18)
    at resolveField (/home/desinv04/estudos/graphql/worldcup-graphql/node_modules/graphql/execution/execute.js:495:16)
    at /home/desinv04/estudos/graphql/worldcup-graphql/node_modules/graphql/execution/execute.js:339:18
    at /home/desinv04/estudos/graphql/worldcup-graphql/node_modules/graphql/jsutils/promiseReduce.js:25:10
    at Array.reduce (<anonymous>)
    at promiseReduce (/home/desinv04/estudos/graphql/worldcup-graphql/node_modules/graphql/jsutils/promiseReduce.js:22:17)
    at executeFieldsSerially (/home/desinv04/estudos/graphql/worldcup-graphql/node_modules/graphql/execution/execute.js:336:38)
    at executeOperation (/home/desinv04/estudos/graphql/worldcup-graphql/node_modules/graphql/execution/execute.js:289:55)
    at executeImpl (/home/desinv04/estudos/graphql/worldcup-graphql/node_modules/graphql/execution/execute.js:154:14)
    at Object.execute (/home/desinv04/estudos/graphql/worldcup-graphql/node_modules/graphql/execution/execute.js:131:229)
    at doRunQuery (/home/desinv04/estudos/graphql/worldcup-graphql/node_modules/apollo-server-core/src/runQuery.ts:194:7)
    at /home/desinv04/estudos/graphql/worldcup-graphql/node_modules/apollo-server-core/src/runQuery.ts:79:39
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:182:7)

TypeError:\u author2.default不是构造函数
在addAuthor（/home/desinv04/estudos/graphql/worldcup graphql/resolvers.js:46:28）
在resolveFieldValueOrError（/home/desinv04/estudos/graphql/worldcup graphql/node_modules/graphql/execution/execute.js:531:18）
在resolveField（/home/desinv04/estudos/graphql/worldcup graphql/node_modules/graphql/execution/execute.js:495:16）
at/home/desinv04/estudos/graphql/worldcup graphql/node_modules/graphql/execution/execute.js:339:18
at/home/desinv04/estudos/graphql/worldcup graphql/node_modules/graphql/jsutils/promiseReduce.js:25:10
在Array.reduce（）处
在promiseReduce（/home/desinv04/estudos/graphql/worldcup graphql/node_modules/graphql/jsutils/promiseReduce.js:22:17）
在ExecuteFieldsSerial（/home/desinv04/estudos/graphql/worldcup graphql/node_modules/graphql/execution/execute.js:336:38）
在执行操作时（/home/desinv04/estudos/graphql/worldcup graphql/node_modules/graphql/execution/execute.js:289:55）
在executeImpl（/home/desinv04/estudos/graphql/worldcup graphql/node_modules/graphql/execution/execute.js:154:14）
在Object.execute（/home/desinv04/estudos/graphql/worldcup graphql/node_modules/graphql/execution/execute.js:131:229）
在doRunQuery（/home/desinv04/estudos/graphql/worldcup graphql/node_modules/apollo server core/src/runQuery.ts:194:7）
at/home/desinv04/estudos/graphql/worldcup graphql/node_modules/apollo server core/src/runQuery.ts:79:39
在
在进程中。_tick回调（internal/process/next_tick.js:182:7）

我不明白为什么会发生此错误，请提前感谢。

尝试以下操作：

import mongoose from 'mongoose';
import uuid from 'node-uuid';
const schema = mongoose.Schema;

const authorSchema = new schema({
    id: {type: String, default: uuid.v1},
    name: String,
    age: Number,
    books: [String]
})

const model = mongoose.model('author', authorSchema);
export default model;

---

引用您的

resolvers.js

文件

从“/model/author”导入authorModel

表示必须从文件

author.js

导出

authorModel

。但看起来不是。从

author.js

文件导出

authorModel

我认为在mongoose中，模式不是模型。您必须首先创建模型：

导出默认mongoose.model（authorSchema）

。请参见文档中的：