Graphql - 获取完整的子对象，如果不存在则为 null [英] Graphql - get full sub-object, or null if doesn't exist

问题描述

我有一个 graphql 查询，它使用 Client 对象获取 Meeting 对象:

type Meeting {地址:字符串！客户:客户}输入客户端{显示名称:字符串！}

displayName 是必需的，但 client 不是.如果我将其查询为

<代码>{getMeeting(会议ID:43bbea6ea0c6112b0abcf11d"){地址客户 {显示名称}}}

而且这次会议没有客户，那么我收到一个错误:

错误:无法为不可为 null 的字段 Client.displayName 返回 null.

我只是希望如果有客户，我会得到它的全部详细信息.如果没有，我会得到 client: null.

如果我从 displayName 中删除所需的，它也会在客户端为空时工作，我会得到

客户端":{显示名称":空}

正如我所料.但我仍在寻找一种方法来强制 displayName 上的要求 - 仅当有客户端时.

有没有办法在graphql中做到这一点?

解决方案

所以问题出在mongoose.

当我从数据库中获取数据时，猫鼬添加了 client: {} 的空嵌入子文档，即使 meeting 文档中没有这样的键在数据库中(并且 console.log(meeting) 不显示此字段 - 只有 console.log(meeting.client) 打印 client: {}).

因此 graphql 尝试返回 client 的必填字段，因为 client 不是我想的 undefined.

I have a graphql query which gets a Meeting object with Client object:

type Meeting {
  address: String!
  client: Client
}
type Client {
  displayName: String!
}

The displayName is required, but client isn't. If I'm querying it as

{
  getMeeting(meetingId: "43bbea6ea0c6112b0abcf11d") {
    address
    client {
      displayName
    }
  }
}

And this meeting doesn't have a client, then I'm getting an error:

Error: Cannot return null for non-nullable field Client.displayName.

I just want that if there is a client, I will get its full details. And if there isn't, I will get client: null.

If I will remove the required from the displayName, it will work also when client is null and I will get

"client": { "displayName": null }

as I've expected. But I'm still looking for a way to enforce the required on the displayName - only if there is a client.

Is there any way to do that in graphql?

解决方案

So the problem was because of mongoose.

When I'm fetching the data from the DB, mongoose adds the empty embedded subdocument of client: {} even if there is no such key in the meeting document in the DB (and console.log(meeting) doesn't show this field - Only console.log(meeting.client) prints client: {}).

Hence graphql tries to return the required field of client, because client is not undefined as I thought.

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