Apollo Graphql模式拼接冲突

Question

我有一个关于GraphQL模式拼接的问题。我有两个Graphql模式：

type Name {
   firstname: String!
   lastname: String!
}

type Address {
   street: String!
   number: Int!
}

type User {
   name: Name!
   address: Address!
}

type Query {
   user(userId: String!): User
}

和

type User {
   age: String!
}

type Query {
   user(userId: String!): User
}

我现在尝试使用graphql工具的mergeSchemas函数合并模式：

const schema = mergeSchemas({
   schemas: [schema1, schema2]
});

但不是我想要实现的（扩展用户类型）：

type Name {
   firstname: String!
   lastname: String!
}

type Address {
   street: String!
   number: Int!
}

type User {
   name: Name!
   address: Address!
   age: String!
}

type Query {
   user(userId: String!): User
}

结果是：type Name{firstname:String！lastname:String！}

type Address {
   street: String!
   number: Int!
}

type User {
   name: Name!
   address: Address!
}

type Query {
   user(userId: String!): User
}

在最终架构中只显示一个UserType。我尝试使用mergeSchemas中的onType冲突API来扩展Type，但没有得到任何结果。

有没有办法通过扩展冲突类型来合并模式？

Answer 1

这应该会有所帮助

extend type User {
   age: String!
}

Answer 2

下面是合并对象类型的可能解决方案。也许在onTypeConflict中按类型名称过滤而不是合并每个类型是有意义的。

import cloneDeep from 'lodash.clonedeep'
import { GraphQLObjectType } from 'graphql/type/definition'
import { mergeSchemas } from 'graphql-tools'

function mergeObjectTypes (leftType, rightType) {
  if (!rightType) {
    return leftType
  }
  if (leftType.constructor.name !== rightType.constructor.name) {
    throw new TypeError(`Cannot merge with different base type. this: ${leftType.constructor.name}, other: ${rightType.constructor.name}.`)
  }
  const mergedType = cloneDeep(leftType)
  mergedType.getFields() // Populate _fields
  for (const [key, value] of Object.entries(rightType.getFields())) {
    mergedType._fields[key] = value
  }
  if (leftType instanceof GraphQLObjectType) {
    mergedType._interfaces = Array.from(new Set(leftType.getInterfaces().concat(rightType.getInterfaces())))
  }
  return mergedType
}

const schema = mergeSchemas({
  schemas: [schema1, schema2],
  onTypeConflict: (leftType, rightType) => {
    if (leftType instanceof GraphQLObjectType) {
      return mergeObjectTypes(leftType, rightType)
    }
    return leftType
  }
})

Credits:mergeObjectTypes函数是由Jared Wolinsky编写的。