我正在用MongooseJS做一个朋友请求，我在MongoDB中存储了一个to和from密钥，它们是发送者和接收者的用户ID。我想防止同一个发送者向同一个接收者发出重复的请求。
下面是我的架构：

import { model, Schema, Document } from 'mongoose';
import { FriendRequestInterface } from '@interfaces/friendrequest.interface';
import { FriendRequestStatus } from '@/enums/enumFriendRequest';

const friendRequestSchema: Schema = new Schema({
  to: {
    type: String,
    required: true,
    // unique: true,
  },
  from: {
    type: String,
    required: true,
    // unique: true,
  },
  message: {
    type: String,
    required: false,
  },
  status: {
    type: String,
    enum: FriendRequestStatus,
    required: true,
  },
});

friendRequestSchema.index({ to: 1, from: 1 }, { unique: true });
const friendRequestModel = model<FriendRequestInterface & Document>('FriendRequest', friendRequestSchema);
export default friendRequestModel;

我发布的内容：

{
    "to": "636acf77378903f78b388339",
    "from": "636acf83378903f78b38833f",
    "message": "Hello, I want to be your friend.",
    "status": "pending"
}

Postman 错误：

{
    "message": "E11000 duplicate key error collection: db_dev.friendrequests index: from_1 dup key: { from: \"636acf83378903f78b38833f\" }"
}