hytopia-events

Use this skill when the user:

• Wants to respond to player actions or game events
• Needs to handle chat commands
• Asks about player input (keyboard, mouse, touch)
• Wants to create custom events
• Needs to handle game lifecycle events (start, end, player join/leave)
• Asks about event prioritization or cancellation

Event Listeners

```typescript

import { World, Player } from 'hytopia';

// Listen for player join

world.onPlayerJoin = (player: Player) => {

console.log(${player.username} joined!);

player.sendMessage('Welcome to the game!');

};

// Listen for player leave

world.onPlayerLeave = (player: Player) => {

console.log(${player.username} left!);

};

// Listen for player chat

world.onPlayerChat = (player: Player, message: string) => {

console.log(${player.username}: ${message});

return true; // Return false to block message

};

```

Chat Commands

```typescript

import { World, Player } from 'hytopia';

world.onPlayerChat = (player: Player, message: string) => {

if (message.startsWith('!')) {

const args = message.slice(1).split(' ');

const command = args[0];

switch (command) {

case 'help':

player.sendMessage('Available commands: !spawn, !teleport, !kit');

break;

case 'spawn':

player.setPosition({ x: 0, y: 100, z: 0 });

player.sendMessage('Teleported to spawn!');

break;

case 'kit':

giveStarterKit(player);

break;

default:

player.sendMessage(Unknown command: ${command});

}

return false; // Don't broadcast command to other players

}

return true; // Allow normal chat

};

```

Player Input

```typescript

import { Player, Input } from 'hytopia';

// Handle player input

player.onInput = (input: Input) => {

if (input.isPressed('space')) {

// Jump

player.applyImpulse({ x: 0, y: 10, z: 0 });

}

if (input.isPressed('e')) {

// Interact

handleInteraction(player);

}

if (input.mouseDelta.x !== 0) {

// Mouse moved horizontally

player.rotation.y += input.mouseDelta.x * 0.1;

}

};

```

Custom Events

```typescript

import { EventEmitter } from 'hytopia';

// Create custom event emitter

const gameEvents = new EventEmitter();

// Define event types

interface GameEvents {

'player-kill': { killer: Player; victim: Player };

'game-start': { map: string };

'game-end': { winner: Player };

}

// Listen for events

gameEvents.on('player-kill', ({ killer, victim }) => {

killer.sendMessage(You eliminated ${victim.username}!);

victim.sendMessage(You were eliminated by ${killer.username}!);

});

// Emit events

gameEvents.emit('player-kill', { killer: player1, victim: player2 });

```

Movement Input

```typescript

player.onInput = (input: Input) => {

const moveSpeed = 5;

const moveDirection = new Vector3(0, 0, 0);

if (input.isPressed('w')) moveDirection.z += 1;

if (input.isPressed('s')) moveDirection.z -= 1;

if (input.isPressed('a')) moveDirection.x -= 1;

if (input.isPressed('d')) moveDirection.x += 1;

if (moveDirection.length() > 0) {

moveDirection.normalize().multiply(moveSpeed);

player.velocity.x = moveDirection.x;

player.velocity.z = moveDirection.z;

}

};

```

Mouse/Click Handling

```typescript

player.onInput = (input: Input) => {

// Left click

if (input.isMousePressed(0)) {

const raycast = world.raycast(player.position, player.lookDirection, 5);

if (raycast.hit && raycast.entity) {

// Attack entity

raycast.entity.takeDamage(10);

}

}

// Right click

if (input.isMousePressed(1)) {

// Place block or use item

useHeldItem(player);

}

};

```

```typescript

import { Game } from 'hytopia';

const game = new Game();

game.onStart = () => {

console.log('Game started!');

// Initialize game state

};

game.onEnd = () => {

console.log('Game ended!');

// Cleanup, save state

};

game.onTick = (deltaTime: number) => {

// Update game logic every frame

updateGameTimer(deltaTime);

checkWinConditions();

};

```

1. Keep event handlers short - delegate to functions for complex logic
2. Return false to cancel - prevent default behavior when needed
3. Use typed events - define interfaces for custom events
4. Clean up listeners - remove listeners when entities despawn
5. Debounce rapid inputs - prevent spamming with cooldowns

• Don't forget to return boolean in chat handler
• Don't block all chat when handling commands (return true for normal messages)
• Don't forget input can be null if player disconnects mid-frame
• Don't rely on client-side input alone - validate on server