我正在从这个youtube视频Next.js 13 Full Course 2023中学习Next.js，在这里他讲述了“匹配”，他用它作为数据的一个要求，通过在那里添加一些代码来匹配他给予的一些属性。

username: {
        type: String,
        required : [true, 'username is required'],
        match: [/^(?=.{8,20}$)(?![_.])(?!.*[_.]{2})[a-zA-Z0-9._]+(?<![_.])$/, "Username invalid, it should contain 8-20 alphanumeric letters and be unique!"], 
    },

我想知道更多关于这种方式的写作比赛，以及如何改变或使自己的，但我找不到任何文件或解释。请帮助我学习如何使用它。我目前使用Nextjs和MongoDB作为数据库和Mongoose。如果需要的话，这里有一个我的pakage.json的副本。

{
  "name": "surveysnap",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "start": "next start",
    "lint": "next lint"
  },
  "dependencies": {
    "autoprefixer": "10.4.15",
    "express": "^4.18.2",
    "mongoose": "^7.5.2",
    "next": "13.4.19",
    "next-auth": "^4.23.1",
    "postcss": "8.4.28",
    "react": "18.2.0",
    "react-dom": "18.2.0",
    "react-icons": "^4.10.1",
    "tailwindcss": "3.3.3"
  }
}

我使用的Schema的完整代码是这样的。

import { Schema, model, models } from "mongoose";
// models is the collection of all the model that is associated with the mongoose library
const UserSchema = new Schema({
    email: {
        type : String,
        unique : [true, 'email already in use'],
        required : [true, 'email already in use'],
    },
    username: {
        type: String,
        required : [true, 'username is required'],
        match: [/^(?=.{8,20}$)(?![_.])(?!.*[_.]{2})[a-zA-Z0-9._]+(?<![_.])$/, "Username invalid, it should contain 8-20 alphanumeric letters and be unique!"], 
    },
    password: {
        type: String,
        match: [/^(?=.{8,20}$)(?![_.])(?!.*[_.]{2})[a-zA-Z0-9._]+(?<![_.])$/, "Password invalid, it should contain 8-20 alphanumeric letters and be unique!"],
    },
    image: {
        type: String,
    },
    membership: {
        type: String,
        required : [true, 'membership is information is required'],
    },
    survey_created: {
        type: Number,
    },
    survey_answered: {
        type: Number,
    },
    snap_points: {
        type: Number,
    },

});

const User = models.User || model("User", UserSchema);
// if a "User" already exists, models assign the existing one to avoid redefining model and ensuring the existing one be used.
// Otherwise it will create a new one.
export default User;

解释如何在Schema中使用Match。