Having different welcome channels - node.js

Question

I need my discord bot to remember which channel to send a greeting to in different guilds.
For now, I have the channel name as a prefix and I use that to recall where to send it:
//greeting new users script
bot.on('guildMemberAdd', member => {
// Send the message to a designated channel on a server:
const WelcomeChannel = member.guild.channels.cache.find(ch => ch.name === config.WelcomeChannelVar);
// Do nothing if the channel wasn't found on this server
if (!WelcomeChannel) return;
const welcomeEmbed = new Discord.MessageEmbed()
.setAuthor(member.displayName.toString() + '#' + member.user.discriminator, member.user.displayAvatarURL())
.setTitle('someone joined!')
.setDescription('welcome to **' + member.guild.name + '**, <#' + member.id + '> !')
.setColor(0x348a58)
.setThumbnail(member.user.avatarURL())
.setFooter('you\'re member #' + member.guild.memberCount + '!')
setTimeout(() => {
WelcomeChannel.send(welcomeEmbed)
}, 200);
member.send("welcome to " + member.guild.name + "! please **read the rules**, and *follow them* :) if you need any help, please **ping a staff member**.");
});
How do I set a command that owners can use when the bot joins their guild that sets a unique welcome channel for each guild (and obviously only send welcome messages to people who join in their guild).
Oh, and how do I set a command that eventually lets people change the welcome message for their guild?
Thanks! :)

Answer 1

You need to have a file where you store the welcome channel IDs for every guild, so that you can later check them. You can just use a JSON file:
// Define it one time
const welcomeChannels = require('./path/to/your/file.json')
// When you want to set the channel for a guild
welcomeChannels[guild.id] = channel.id
fs.writeFileSync('./path/to/your/file.json', JSON.stringify(welcomeChannels))
// When you need to read a property
let welcomeChannelID = welcomeChannels[guild.id]
You can use a variable to store the object, which is saved to a file that you can update with fs.writeFileSync.
Inside the guildMemberAdd handler, you can get the guild id from the new member and then use it to get the channel id:
bot.on('guildMemberAdd', member => {
let id = welcomeChannels[member.guild.id]
let welcomeChannel = member.guild.channels.cache.get(id)
// The rest is the same as in your code
})
Example
In the main file you just need to require it for the first time and use it in your guildMemberAdd handler.
// main file
const welcomeChannels = require('./path/to/your/file.json')
bot.on('guildMemberAdd', member => {
let id = welcomeChannels[member.guild.id]
let welcomeChannel = member.guild.channels.cache.get(id)
// The rest is the same as in your code
})
For the command it really depends on your command system: you need to find a way of sharing the welcomeChannels variable across the files, which is typically done though import/export Here's a mock function on how to set a new value.
// command file
function setId(guildID, channelID) {
welcomeChannels[guild.id] = channel.id
fs.writeFileSync('./path/to/your/file.json', JSON.stringify(welcomeChannels))
}