如何在Apollo graphql服务器中创建嵌套的解析器 [英] How to create a nested resolver in apollo graphql server

问题描述

给出以下apollo服务器graphql模式 我想将它们分解成单独的模块，所以我不想在根查询模式下使用作者查询.因此，在将其添加到根查询之前，我添加了另一个名为authorQueries的层

Given the following apollo server graphql schema I wanted to break these down into separate modules so I don't want the author query under the root Query schema.. and want it separated. So i added another layer called authorQueries before adding it to the Root Query

type Author {
    id: Int,
    firstName: String,
    lastName: String
}  
type authorQueries {
    author(firstName: String, lastName: String): Author
}

type Query {
    authorQueries: authorQueries
}

schema {
    query: Query
}

我尝试了以下操作..您可以看到在指定author函数之前，authorQueries已添加为另一层.

I tried the following.. you can see that authorQueries was added as another layer before the author function is specified.

Query: {
    authorQueries :{
        author (root, args) {
            return {}
       }
    }
}

在Graphiql中查询时，我还添加了该额外的层.

When querying in Graphiql, I also added that extra layer..

{
    authorQueries {
        author(firstName: "Stephen") {
            id
        }
    }
}

我收到以下错误消息.

"message": "Resolve function for \"Query.authorQueries\" returned undefined",

推荐答案

要创建嵌套"解析器，只需在父字段的返回类型上定义解析器.在这种情况下，您的authorQueries字段返回类型authorQueries，因此您可以将解析器放在此处:

To create a "nested" resolver, simply define the resolver on the return type of the parent field. In this case, your authorQueries field returns the type authorQueries, so you can put your resolver there:

{
  Query: { authorQueries: () => ({}) },
  authorQueries: {
    author(root, args) {
      return "Hello, world!";
    }
  }
}

因此，从技术意义上讲，没有嵌套的解析器之类的东西-每个对象类型都有一个平面字段列表，而这些字段具有返回类型. GraphQL查询的嵌套是使结果嵌套的原因.

So in the technical sense, there is no such thing as a nested resolver - every object type has a flat list of fields, and those fields have return types. The nesting of the GraphQL query is what makes the result nested.

这篇关于如何在Apollo graphql服务器中创建嵌套的解析器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！