如何通过user_id获取MongoDB中invites表的invite_link值（discord.js v14）

我正在用discord.js v14开发Discord机器人，希望仅通过user_id从MongoDB的invites表中获取对应的invite_link值，请问这是否可行？

以下是我当前的实现代码：

const { SlashCommandBuilder } = require("@discordjs/builders")
const Discord = require("discord.js")
const { QuickDB } = require("quick.db");
const db2 = new QuickDB();
const mongodb = require("mongodb");

const username = encodeURIComponent('censored');
const password = encodeURIComponent("censored")
const dbname = 'censored';
const fetch = (...args) => import('node-fetch').then(({default: fetch}) => fetch(...args));
const clusterUrl = "censored";
const authMechanism = "DEFAULT";
const url = `mongodb://${username}:${password}@${clusterUrl}/${username}`;
const client = new mongodb.MongoClient(url);    
const db = client.db(dbname)
client.connect().then(() => {
    console.log("Data: Connected")
}).catch(err => console.error(err)) 


module.exports = { 
    data: new SlashCommandBuilder()
        .setName("invite")
        .setDescription("Create invite to download server"),

    execute: async function(interaction, guilds, client, invites) {
        if(interaction instanceof Discord.CommandInteraction) {


const guild = interaction.client.guilds.cache.get(`1013773663910232184`)
if(await db.collection('blacklist').findOne({
    user_id: `${interaction.member.id}`
 })){
    return interaction.reply({ content: `You cant acces to this command! (Error code: 502)`, ephemeral: true})
 }

 const query = { user_id: `${interaction.member.id}` };

const options = {
   projection: { invite_link: 1 } //only return invite link
};

const inviteLink2 = await db.collection('invites').findOne(query, options);

 if(await db.collection('invites').findOne({
    user_id: `${interaction.member.id}`
 })) {
    return interaction.reply({ content: `You always have invite code! This is your invite code: ${inviteLink2}`})
 }

 



        const invitecode = await guild.invites.create('1013793499189100574', { maxAge: 18000, maxUses: 1} );
        db.collection('invites').insertOne({
            user_id: `${interaction.member.id}`,
            invite_link: `${invitecode.url}`
     })
        interaction.reply({ content: `This is your invite: ${invitecode.url} , DO NOT SEND THIS LINK TO ANYONE. Invite expires in 3 minutes.`, ephemeral: true})
        
        

console.log(`${invitecodegetindatabase}`)

        }   

        }
    }

完全可行，通过MongoDB的findOne方法结合查询条件和投影参数，就能仅获取目标字段。不过你的代码存在几个问题，需要优化：

1. 重复数据库查询：你先执行了一次findOne获取inviteLink2，之后又重复执行一次判断用户是否存在。可以直接用第一次查询的结果判断，减少数据库操作：

   const inviteLinkDoc = await db.collection('invites').findOne({ user_id: interaction.member.id }, { projection: { invite_link: 1, _id: 0 } });
   if (inviteLinkDoc) {
       // 用户已有邀请链接
   }
   

2. 回复内容错误：直接输出inviteLink2会返回整个文档对象（显示[object Object]），需要提取invite_link字段：

   return interaction.reply({ content: `你已经有邀请链接了！链接是：${inviteLinkDoc.invite_link}`, ephemeral: true })
   

3. 未定义变量报错：代码末尾的invitecodegetindatabase未定义，会导致控制台报错，建议移除该语句。

4. 连接逻辑优化：当前MongoDB连接逻辑放在全局，虽然能工作，但建议将连接封装成单独函数，确保连接成功后再执行命令，避免因连接未就绪导致的错误。

优化后的核心代码片段： #

execute: async function(interaction, guilds, client, invites) {
    if(interaction instanceof Discord.CommandInteraction) {
        const guild = interaction.client.guilds.cache.get('1013773663910232184');
        // 黑名单判断
        const isBlacklisted = await db.collection('blacklist').findOne({ user_id: interaction.member.id });
        if (isBlacklisted) {
            return interaction.reply({ content: '你无法使用此命令！(错误代码: 502)', ephemeral: true });
        }

        // 查询用户已有邀请链接
        const inviteLinkDoc = await db.collection('invites').findOne(
            { user_id: interaction.member.id },
            { projection: { invite_link: 1, _id: 0 } } // 只返回invite_link，排除默认的_id字段
        );

        if (inviteLinkDoc) {
            return interaction.reply({ content: `你已经有邀请链接了！链接是：${inviteLinkDoc.invite_link}`, ephemeral: true });
        }

        // 创建新邀请并保存到数据库
        const invitecode = await guild.invites.create('1013793499189100574', { maxAge: 18000, maxUses: 1 });
        await db.collection('invites').insertOne({
            user_id: interaction.member.id,
            invite_link: invitecode.url
        });

        interaction.reply({ content: `这是你的邀请链接：${invitecode.url}，请勿转发给他人。邀请链接将在3分钟后过期。`, ephemeral: true });
    }
}

内容的提问来源于stack exchange，提问作者Smkv 2022