可以計算 type-graphql 中的結果列表元素

Question

我是 typeGraphQL 的新手，我的問題是可能對結果列表元素進行計數

我有模型類型的書

import { Field, ID, ObjectType, Root } from "type-graphql";
import { Model, Column } from "sequelize-typescript";


@ObjectType()
export default class Books extends Model<Books> 
{

    @Field(() => ID)
    @Column
    id: number;

    @Field(() => String)
    @Column
    bookName: string;

}

在解析器中查詢

@Query(() => [Books])
async getBooks()
{
    return Books.findAll()
}

在 graphiQL 中運行查詢時

getTest
{
    id
    bookName
}

得到回應

"getBooks" : 
[
    {
        "id": "1",
        "bookName": "bookOne"
    },
    {
        "id": "2",
        "bookName": "bookTwo"
    }
]

但我需要添加附加字段，例如獲取所有收到項目的總計數。 如何正確地做到這一點？ 現在我們必須創建一個單獨的查詢，但是對於大樣本來說，這是非常不方便的，並且會導致重復復雜和大的查詢

@Query(() => [Books])
async countBooks()
{
    return Books.findAll().length
}

我嘗試為元素數量和模型本身創建一個單獨的聯合類型

@ObjectType()
export default class UnionType extends Model<UnionType> 
{

    @Field(() => [Books])
    books: Books[];

    @Field(() => Int)
    totalCount(@Root() parent : UnionType) : number 
    {
        return parent.books.length;
    }

}

並在解析器中運行下一個查詢

@Query(() => [UnionType])
async getBooksAndCountAll()
{
    let union : any = {}        

    union.books = Books.findAll();
    union.totalCount = union.books.length;

    return union;
}

但是在運行查詢error "message": "Expected Iterable, but did not find one for field Query.getBooks.",據我所知，它沒有傳輸模型期望的數據

我嘗試使用 createUnionType

import { createUnionType } from "type-graphql";
const SearchResultUnion = createUnionType({
    name: "Books", // the name of the GraphQL union
    types: [Books, CountType], // array of object types classes
  });

其中 UnionType

@ObjectType()
export default class CountType extends Model<CountType> 
{
    @Field(() => Int, { nullable : true })
    totalCount: number;
}

在解析器中查詢

    @Query(returns => [SearchResultUnion])
    async getBooks(
    ): Promise<Array<typeof SearchResultUnion>>{

        return new Promise((resolve, reject) => {
            Books.findAll()
            .then(books => {

                let totalCount = books.length;

                return [...books, ...totalCount];
            });
        });
    }

但是在字符串return [...books, ...totalCount]; на ...totalCount Type 'number' must have a '[Symbol.iterator]()' method that returns an iterator.

如果你不通過...totalCount請求有效，但是沒有分別已經沒有totalCount

getTest{
__typename
  ... on Books
  {
    id
    bookName
  }
}

要求

 "getBooks": [
    {
        "id": "1",
        "bookName": "bookOne"
    },
    {
        "id": "2",
        "bookName": "bookTwo"
    }
  ]

所以，結果我需要一個請求

getTest
{
    totalCount
    __typename
      ... on Books{
        id
        bookName
      }
}

可能嗎？

Answer 1

來自https://github.com/19majkel94/的答案
謝謝，邁克爾·萊泰克

@ObjectType()
export default class GetBooksResponse {
    @Field(() => [Books])
    books: Books[];

    @Field(() => Int)
    totalCount : number;
}

@Query(() => GetBooksResponse)
async getBooks() {
  const books = await Books.findAll();
  return { books, totalCount: books.length };
}