如何在graphql中重用解析器

Posted 2023-03-10

【中文标题】如何在graphql中重用解析器

【英文标题】：how to reuse resolvers in graphql

【发布时间】：2017-10-03 23:10:33

【问题描述】：

我是 graphql 的新手，我正在使用 graphql 创建以下架构

// promotion type

const PromoType = new GraphQLObjectType(
  name: 'Promo',
  description: 'Promo object',
  fields: () => (
    id: 
      type: GraphQLID,
      description: 'id of the promo'
    ,
    title: 
      type: GraphQLString,
      description: 'this is just a test'
    ,
    departments: 
      type: new GraphQLList(DepartmentType),
      description: 'departments associated with the promo'
    
  )
)

部门类型

// department type

const DepartmentType = new GraphQLObjectType(
  name: 'Department',
  description: 'Department object',
  fields: () => (
    id: 
      type: GraphQLID,
      description: 'id of the department'
    ,
    name: 
      type: GraphQLString,
      description: 'name of the department'
    ,
    createdAt: 
      type: GraphQLDate,
      description: 'date the promo is created'
    ,
    updatedAt: 
      type: GraphQLDate,
      description: 'date the promo is last updated'
    
  )
);

以下是解析器

// Promos resolver

const promos = 
  type: new GraphQLList(PromoType),
  resolve: (_, args, context) => 

    let promos = getPromos()
    let departments = getDepartmentsById(promos.promoId)
    return merge(promos, departments)
  
;


//Departments resolver
const departments = 
  type: new GraphQLList(DepartmentType),
  args: 
      promoId: 
      type: GraphQLID
    
  ,
  resolve: (_, args, context) => 

    return getDepartmentsById(args.promoId)
  
;

问题是我想使用部门的解析器进入促销的解析器来获取部门。

我可能遗漏了一些明显的东西，但有什么办法可以做到这一点？

【参考方案1】：

这是实现它的方法。您想将其视为图形，而不仅仅是单个休息端点。

要获取Promo 的数据，您需要与我在此处的操作类似，但对于父节点，如果这有意义的话。所以，在例如查看者决定您添加查询Promo。

const PromoType = new GraphQLObjectType(
  name: 'Promo',
  description: 'Promo object',
  fields: () => (
    id: 
      type: GraphQLID,
      description: 'id of the promo',
    ,
    title: 
      type: GraphQLString,
      description: 'this is just a test',
    ,
    departments: 
      type: new GraphQLList(DepartmentType),
      description: 'departments associated with the promo',
      resolve: (rootValue) => 
        return getDepartmentsById(rootValue.promoId);
      
    
  )
);

【讨论】：

我的意思是我不想为单个字段编写解析器，如果有任何“自动”方法可以做到这一点。我已经使用了 Apollo 工具和服务器。