GraphQL 连接

Question

我与用户及其成员之间存在这种关系。 memberships 字段是一个用户和多个memberships 之间的连接。

const MembershipType = new GraphQLObjectType({
  name: 'Membership',
  interfaces: [nodeInterface],

  fields: {
    id: globalIdField(),

    user: {
      type: new GraphQLNonNull(UserType),
      resolve(parent, args, ctx: Context) {
        return ctx.userById.load(parent.user_id);
      },
    },

    role: {
      type: new GraphQLNonNull(GraphQLString),
    },

    team: {
      type: GraphQLString,
    },

    createdAt: {
      type: new GraphQLNonNull(GraphQLString),
      resolve(parent) {
        return parent.created_at;
      },
    },

    updatedAt: {
      type: new GraphQLNonNull(GraphQLString),
      resolve(parent) {
        return parent.updated_at;
      },
    },
  },
});

export default MembershipType;


const UserType = new GraphQLObjectType({
  name: 'User',
  interfaces: [nodeInterface],

  fields: {
    id: globalIdField(),

    firstName: {
      type: GraphQLString,
      resolve(parent) {
        return parent.first_name;
      },
    },

    lastName: {
      type: GraphQLString,
      resolve(parent) {
        return parent.last_name;
      },
    },

    email: {
      type: GraphQLString,
      resolve(parent) {
        return parent.email;
      },
    },

    memberships: {
      type: new GraphQLList(MembershipType),
      resolve(parent, args, ctx: Content) {
        return ctx.membershipsByUserId.load(parent.id);
      },
    },

    membershipsCount: {
      type: new GraphQLNonNull(GraphQLInt),
      resolve(parent, args, ctx: Context) {
        return ctx.userMembershipsCount.load(parent.id);
      },
    },
  },
});

export default UserType;

这里的问题是我有这个错误，其中 MembershipType 中的用户字段导致错误

Blockquote /Users/nizarayari/Arise/arise-auth/node_modules/graphql/jsutils/invariant.js:19 throw new Error(message); ^ Error: Expected undefined to be a GraphQL nullable type. at invariant (/Users/nizarayari/Arise/arise-auth/node_modules/graphql/jsutils/invariant.js:19:11) at assertNullableType (/Users/nizarayari/Arise/arise-auth/node_modules/graphql/type/definition.js:261:51) at new GraphQLNonNull (/Users/nizarayari/Arise/arise-auth/node_modules/graphql/type/wrappers.js:79:54) at Object. (/Users/nizarayari/Arise/arise-auth/src/schema/membership/MembershipType.js:25:13) at Module._compile (module.js:624:30) at Object.Module._extensions..js (module.js:635:10) at Module.load (module.js:545:32) at tryModuleLoad (module.js:508:12) at Function.Module._load (module.js:500:3) at Module.require (module.js:568:17) at require (internal/module.js:11:18) at Object. (/Users/nizarayari/Arise/arise-auth/src/schema/user/UserType.js:19:1) at Module._compile (module.js:624:30) at Object.Module._extensions..js (module.js:635:10) at Module.load (module.js:545:32) at tryModuleLoad (module.js:508:12)

这是我对用户的查询

import UserType from './UserType';
import type Context from '../../Context';

const me = {
  type: UserType,
  resolve(root: any, args: any, ctx: Context) {
    return ctx.user && ctx.userById.load(ctx.user.id);
  },
};

export default {
  me,
};

没有成员查询只是突变

Answer 1

您可能需要将文件中的 UserType 移动到 MembershipType 上方。

let Foo = {
  bar: Bar
}

let Bar = 'bar'

console.log(Foo.bar) // undefined

Foo = {
  bar: Bar
}

console.log(Foo.bar) // 'bar'

https://repl.it/@tcoughlin3/CumbersomeClassicRat

Answer 2

两个字段是否在同一个js文件中？您在看起来像同一个 js 文件的 Memberships 和 UserType 上都有 export default。

您只能在每个文件的一个字段上使用 export default。

将两个字段分开后，由于 Membership 取决于 UserType，技巧是使用 returns Membership

中的字段对象的函数

const MembershipType = new GraphQLObjectType({
  name: 'Membership',
  interfaces: [nodeInterface],
  fields: () => ({
    id: globalIdField(),
    ...
  })
});

而不是：

const MembershipType = new GraphQLObjectType({
  name: 'Membership',
  interfaces: [nodeInterface],
  fields: {
    id: globalIdField(),
    ...
  }
});

GraphQL 连接

GraphQL Connections

javascript

graphql

graphql-js

relay

express-graphql