如何嵌套 graphql 查询

Question

我找到的所有示例都有一个 query 顶级对象，然后是一个查询列表，然后 return 键入更深入的内容。

由于我有大量查询，我想将它们分组，这是我尝试过的：

const AppType = new GraphQLObjectType({
    name: 'App',
    description: 'Generic App Details',

    fields: () => ({
        name: { type: GraphQLString },
        appId: { type: GraphQLInt },
    }),
});

const MyFirstQuery = {
    type: new GraphQLList(AppType),
    args: {
        appId: { type: GraphQLInt },
    },
    resolve: (root, args) => fetchApp(args.appId),
};     

/* snip MySecondQuery, MyThirdQuery, MyFourthQuery */

const MyFirstGroupQuery = new GraphQLObjectType({
    name: 'myFirstGroup',
    description: 'the first group of queries',

    fields: () => ({
        myFirstQuery: MyFirstQuery,
        mySecondQuery: MySecondQuery,
        myThirdQuery: MyThirdQuery,
        myFourthQuery: MyFourthQuery,
    }),
});

/* snip MySecondGroupQuery, MyThirdGroupQuery and their types */    

const QueryType = new GraphQLObjectType({
    name: 'query',
    description: 'read-only query',

    fields: () => ({
        myFirstGroup: MyFirstGroupQuery,
        mySecondGroup: MySecondGroupQuery,
        myThirdGroup: MyThirdGroupQuery,
    }),
});

const Schema = new GraphQLSchema({
    query: QueryType,
});

为什么我不能像 QueryType 那样制作 MyFirstGroupQuery 来制作更多的嵌套层次？如果我将所有查询放在 QueryType 中，代码工作正常，但我的 MyFirstGroupQuery 产生错误：

Error: query.myFirstGroup field type must be Output Type but got: undefined.

如何完成我想要的？我真的不想只为所有查询添加前缀。

Answer 1

错误 query.myFirstGroup field type must be Output Type but got: undefined. 表示您没有提供 myFirstGroup 的类型您必须使用 type 字段

提供类型

myFirstGroup: { type: MyFirstGroupQuery, resolve: () => MyFirstGroupQuery, },

并且如果类型 MyFirstGroupQuery 每个字段必须具有 type 定义，例如 GraphQLInt、GraphQLString、GraphQLID，即使它是自定义类型MyFirstGroupQuery

在 GraphQLSchema 构造函数中，您提供 RootQuery 即 QueryType，这是一个 GraphQLSchema 它只接受 rootQuery 和 GraphQLObjectType 其字段必须定义 type

GraphQL 是严格基于类型的，您声明的每个字段都必须type定义

https://github.com/graphql/graphql-js

https://github.com/graphql/graphql-js/blob/master/src/type/schema.js#L32

const {
    GraphQLID,
    GraphQLInt,
    GraphQLString,
    GraphQLObjectType,
    GraphQLSchema,
    GraphQLList,
} = require('graphql');

const AppType = new GraphQLObjectType({
    name: 'App',
    description: 'Generic App Details',

    fields: () => ({
        name: { type: GraphQLString },
        appId: { type: GraphQLInt },
    }),
});

// const MyFirstQuery = {
//     type: new GraphQLList(AppType),
//     args: {
//         appId: { type: GraphQLInt },
//     },
//     resolve: (root, args) => fetchApp(args.appId),
// };

const myFirstQuery = new GraphQLObjectType({
    name: 'First',
    fields: () => ({
        app: {
            type: new GraphQLList(AppType),
            args: {
                appId: { type: GraphQLInt },
            },
            resolve: (root, args) => fetchApp(args.appId),
        },
    }),
});

/* snip MySecondQuery, MyThirdQuery, MyFourthQuery */

const MyFirstGroupQuery = new GraphQLObjectType({
    name: 'myFirstGroup',
    description: 'the first group of queries',
    fields: () => ({
        myFirstQuery: {
            type: myFirstQuery,
            resolve: () => [], // promise
        },
        // mySecondQuery: {
        //     type: MySecondQuery,
        //     resolve: () => //data
        // }
        // myThirdQuery: {
        //     type: MyThirdQuery,
        //     resolve: () => // data
        // }
        // myFourthQuery: {
        //     type: MyFourthQuery,
        //     resolve: () => //data
        // }
    }),
});

/* snip MySecondGroupQuery, MyThirdGroupQuery and their types */

const QueryType = new GraphQLObjectType({
    name: 'query',
    description: 'read-only query',

    fields: () => ({
        myFirstGroup: {
            type: MyFirstGroupQuery,
            resolve: () => MyFirstGroupQuery,
        },
        // mySecondGroup: {
        //     type: MySecondGroupQuery,
        //     resolve: MySecondGroupQuery
        // }
        // myThirdGroup: {
        //     type: MyThirdGroupQuery,
        //     resolve: MyThirdGroupQuery
        // }
    }),
});

const Schema = new GraphQLSchema({
    query: QueryType,
});

module.exports = Schema;

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