Building a Custom Command System

Create a chat-based command system for your realm with custom commands, permissions, and help.

Why Custom Commands?

It's a more simple way to add custom commands rather than registering a ton of /commands. A command system lets you build your own: !tp, !home, !shop, etc. By intercepting chat messages that start with !, you can parse them and execute custom logic.

The basic pattern: listen to chat, check if it's a command, parse arguments, execute logic.

Basic Command Parser

The foundation: catch chat messages starting with ! and route them to handlers:

world.beforeEvents.chatSend.subscribe((event) => {
  const message = event.message;
  
  if (!message.startsWith("!")) return;
  
  event.cancel = true;
  
  const parts = message.slice(1).split(" ");
  const command = parts[0];
  const args = parts.slice(1);
  
  handleCommand(event.sender, command, args);
});

function handleCommand(player, command, args) {
  switch (command) {
    case "help":
      showHelp(player);
      break;
    case "teleport":
      teleportCommand(player, args);
      break;
    case "give":
      giveCommand(player, args);
      break;
    default:
      player.sendMessage("§cUnknown command");
  }
}

Permission Checks

Not all players should be able to run all commands. Teleporting admins might want to restrict who can use certain features. This function checks if a player has permission:

const admins = ["admin_uuid_1", "admin_uuid_2"];

function hasPermission(player, permission) {
  if (admins.includes(player.id)) return true;
  
  switch (permission) {
    case "admin":
      return admins.includes(player.id);
    case "mod":
      return admins.includes(player.id); // Could expand this
    default:
      return true;
  }
}

function teleportCommand(player, args) {
  if (!hasPermission(player, "admin")) {
    player.sendMessage("§cYou don't have permission for this command");
    return;
  }
  
  if (args.length < 3) {
    player.sendMessage("§cUsage: /tp <x> <y> <z>");
    return;
  }
  
  const [x, y, z] = args.map(Number);
  player.teleport({ x, y, z });
}

Command with Cooldown

Commands can be abused - players might spam teleport or spam gifts. A cooldown prevents this by forcing users to wait between uses:

const cooldowns = new Map();

function teleportCommand(player, args) {
  const now = Date.now();
  const cooldownTime = 5000; // 5 seconds
  
  if (cooldowns.has(player.id)) {
    const lastUse = cooldowns.get(player.id);
    const remaining = Math.ceil((cooldownTime - (now - lastUse)) / 1000);
    
    if (now - lastUse < cooldownTime) {
      player.sendMessage(`§cPlease wait ${remaining}s`);
      return;
    }
  }
  
  cooldowns.set(player.id, now);
  player.sendMessage("§aCommand executed!");
}

Help System

const commands = {
  help: { description: "Show this help message" },
  teleport: { description: "Teleport to coordinates", usage: "/tp <x> <y> <z>" },
  give: { description: "Give items to players", usage: "/give <player> <item>" }
};

function showHelp(player) {
  player.sendMessage("§6=== Commands ===");
  
  Object.entries(commands).forEach(([cmd, info]) => {
    player.sendMessage(`§e!${cmd}§r - ${info.description}`);
    if (info.usage) {
      player.sendMessage(`  §7${info.usage}`);
    }
  });
}

Best Practices

• Always validate arguments
• Provide clear error messages
• Use permission systems for admin commands
• Implement cooldowns to prevent spam
• Log important command executions