Item, NPC, and Room scripting comes in the form of event-based scripting. See the Event section for a general overview of how Ranvier eventing works before reading on.

Creating a script

Scripts are defined for an area in the scripts/ folder underneath the area's folder. For each entity type there is a subfolder. For example:


As a matter of convention scripts are named, <entity id>-<whatever you want>. It's not required but it will help a lot when trying to figure out what script goes to what entity.

See the relevant entity's guide section on how to add the script to the entity.


Behaviors are scripts that you can reuse for the same entity types across multiple areas/bundles. For example, maybe you want to have many different NPCs wander around at random, or immediately attack players upon entering the room; you can use behaviors to re-use the same script.

Behaviors are defined similarly to normal scripts, and also rely on events, but are created inside the behaviors/ directory inside your bundle, which is outside of your areas/ directory. Another key difference is that they are configurable in the entity's .yaml definition (see each entity type's documentation for some examples, and below for details on configuration).


Again, see the relevant entity type's scripting guide section below for more on how to add behaviors to that entity.

Tip: Behaviors can be used as flags. For example, if you say behaviors: ['combat'] on an NPC, you don't need to actually create a combat.js behavior file, npc.hasBehavior('combat') will still return true. This is used, as an example, in the kill command in ranvier-combat to differentiate pacifist NPCs from NPCs that can enter combat.

File Structure

Entity-specific scripts and Behavior script files follow the same file structure outlined here:

'use strict';

module.exports = srcPath => {
  return {
    The familiar bundle script file format we've seen in commands and quests returns here.
    To listen for an event, simply add a new key (which is the event name) to 'listeners'. The value for each listener is a closure accepting GameState (seen here as state, see the Ranvier server executable for more) and returning a function
    whose arguments are dependent on the event. See the Default Events section below for
    to see some examples of arguments being passed to the listeners.
    listeners: {
      someEvent: state => (/* event args */) => {
        // do stuff here

NOTE: Behaviors are written differently because the first argument to their listener is always config, an object that will be equal to the behavior config as defined in that entity's yml file. As an example, the following is what an item with a 'test' behavior that listens for the 'foo' event would look like:

In items.yml:

- id: 9
  name: 'My Item'
      hello: "World"

When event is fired:

// the config is automatically prepended to the arguments, you DO NOT have to manually
// send it in when emitting events
myItem.emit('foo', player, 'baz');

In your behavior listeners:

listeners: {
  foo: state => (config, player, thing) => {
    This will output as per the 'test' behaviors config in items.yml
      hello: "World"
    console.log(player, thing); /* Player, 'baz' */

Default events

This is a list of events that are emitted by default in Ranvier, from one of two sources:

Engine - Events that come from the engine itself (from src/) and will always be available.

Default Bundles - Events that come from one of the ranvier-* bundles and may not be available if you have disabled them.

Events are shown as:
eventName (ArgumentType arguments)
Details of event



Combat has ended, emitted when an NPC's list of combatants becomes empty
combatStart (Character target)
Combat has started against target, emitted when NPC was not in combat and now is. Event is not fired if the NPC was already in combat when new combatants are added
damaged (Damage damage)
Something has decreased one of the NPC's attributes. This emits when any attribute is damaged, not just health. See src/Damage.js for details of information available from damage argument.
healed (Heal heal)
Same as damaged but increased attribute instead of decreased.
hit (Damage damage, Character target)
This NPC caused damage to the target. Target may be itself.
heal (Heal heal, Character target)
Same as hit but increased attribute instead of decreased.
NPC is initially created; this event emits immediately after NPC is placed in its target room.
This event is special in that it automatically fires every tenth of a second on Rooms, Items, NPCs, and Players. This event should be used for any event that is based on time, e.g., NPC should wander around every N seconds.

Core Bundles

deathblow (Character target)
NPC just killed target.
NPC died.
playerDropItem (Player player, Item item)
player just dropped item in the room with the NPC.
playerEnter (Player player)
player just entered the room with the NPC.
playerLeave(Player player)
player just left the room. NOTE: playerLeave is actually fired before the player is removed from the room.



See updateTick under NPCs.

Core Bundles

drop (Player player)
player just dropped this item.
equip (Player player)
player just equipped this item.
get (Player player)
player just picked up this item.
put (Player player, Item container)
player just put this item into container.



See updateTick for NPCs.

Core Bundles

playerEnter (Player player)
player just entered this room.
playerLeave(Player player)
player just left this room. NOTE: playerLeave is actually fired before the player is removed from the room.