@unknown-user on discord server welcome

import {
  Guild,
  GuildMember,
  MessageCreateOptions,
  TextChannel,
} from "discord.js";
import { Discord, On } from "discordx";
import { bot } from "../classes/discord-bot.js";
import { createUserApplyButtonRow } from "../commands/onboarding-setup.js";
import { OnboardingService } from "../services/onboarding-service.js";
import { logger } from "../util/logger.js";

@Discord()
export class WelcomeEvent {
  @On({ event: "guildMemberAdd" })
  async onMemberJoin(members: GuildMember[]): Promise<void> {
    for (const member of members) {
      let fetchedMember: GuildMember = member;
      try {
        // Fetch the member to ensure all data is loaded
        fetchedMember = await member.fetch();
      } catch (error) {
        logger.error(
          `Unable to fetch new guildmember with id ${member.id}`,
          error
        );
      }

      const config = OnboardingService.getConfig(fetchedMember.guild.id);
      if (!config.welcomeText && !config.welcomeChannelId) return;

      const welcomeChannel = fetchedMember.guild.channels.cache.get(
        config.welcomeChannelId
      ) as TextChannel;
      if (!welcomeChannel) {
        logger.warn(
          "Onboarding welcome channel by id was not found in cache",
          config.welcomeChannelId,
          config.discordGuildName
        );
        return;
      }

      const joinButtons = createUserApplyButtonRow(
        config.enableWelcomeClanOnboarding,
        config.enableWelcomeFriendOnboarding
      );

      const greeting = transformedWelcomeText({
        welcomeText: config.welcomeText,
        newUser: fetchedMember,
        guild: bot.guilds.cache.find((g) => g.id === config.discordGuildId)!,
      });

      const sendOptions: MessageCreateOptions = {
        content: greeting,
      };

      if (
        config.enableWelcomeClanOnboarding ||
        config.enableWelcomeFriendOnboarding
      ) {
        sendOptions.components = [joinButtons];
      }

      try {
        logger.info("Sending welcome text to welcome channel");
        await welcomeChannel.send(sendOptions);
      } catch (error) {
        logger.error("Unable to send welcome text to welcome channel", error);
      }
    }
  }
}

function transformedWelcomeText(data: {
  welcomeText: string;
  newUser: GuildMember;
  guild: Guild;
}): string {
  const { guild, newUser, welcomeText } = data;
  const changes = new Map<string, string>([
    ["[ServerName]", guild.name],
    ["[UserMention]", `<@${newUser.id}>`], // Works better then userMention, as fetching the user might fail.
  ]);

  let result = welcomeText;
  changes.forEach((v, k) => {
    result = result.replaceAll(k, v);
  });

  return result;
}