Node.js 如何在Mongoose for MongoDB中编写此查询

我有两个文档模式，User和Skill.

User具有引用Skill的skills属性.

Skill有一个users属性，它引用了User.

我想能够查询的用户谁有一定的技能.

export async function getUsersWithSkill(skillName: SkillName): Promise<User[]> {
  // NOTE : 'CONNECTION' is the mongoose connection to MongoDB
  const Users = CONNECTION.model<User>('User');

  const users: User[] = await Users
    .find() // does it need a condition in find?
    .populate({
      path: 'skills',
      match: {
        name: { $eq: skillName }
      }
    })
    // or does it need a where clause here?
    // 
    // the following didn't work
    // .where({
    //   skills: { $count : { $gt: 0 }}
    // })
    .exec();

  return users;
}

在上面的代码中，populate如预期的那样工作，只填充与`panate中的match条件匹配的技能.

模式内容如下所示:

import { Document, Schema } from 'mongoose';
import { Skill } from './Skill';

export interface User extends Document {
  firstName: string;
  lastName: string;
  skills: Skill[];
}

export const UserSchema: Schema<User> = new Schema<User>({
  firstName: {
    type: String,
    required: true
  },
  lastName: {
    type: String,
    required: true
  },
  skills: [{
    type: Schema.Types.ObjectId,
    ref: 'Skill'
  }]
});

export interface Skill extends Document {
  name: string;
  users: User[]
}

export const SkillSchema: Schema<Skill> = new Schema<Skill>({
  name: {
    type: String,
    required: true,
    enum: Object.values(SkillName)
  },
  users: [{
    type: Schema.Types.ObjectId,
    ref: 'User'
  }]
});

export enum SkillName {
  CSHARP = 'CSHARP',
  FSHARP = 'FSHARP',
  JAVA = 'JAVA',
  JAVASCRIPT = 'JAVASCRIPT',
  TYPESCRIPT = 'TYPESCRIPT',
  PYTHON = 'PYTHON',
  PERL = 'PERL',
  BASH = 'BASH'
}