Bedrock Edition scripting documentation

This is the scripting documentation for Bedrock Edition 1.12.0.

Version: 1.12.0.28

Scripting system

The Minecraft Script Engine uses the JavaScript language.

The player can write JavaScript scripts and bundle them with Behavior Packs to listen and respond to game events, get and modify data in components that entities have, and affect different parts of the game.

Demos

Here are some demos from your friends at Minecraft to help you get started with scripting. Simply unzip them to check out the code, or import them as a .mcpack to play with them.

Demo	Last Updated	Download Link
Turn-Based RPG	4/17/2019	https://aka.ms/minecraftscripting_turnbased
Mob Arena	4/17/2019	https://aka.ms/minecraftscripting_mobarena

Known issues

This is the list of currently known issues with the Minecraft Script Engine.

Issue	Workaround
Scripts are not loaded properly from archived packs	Unzip script packs before applying them to a world. If you import a script pack with the .mcpack extension, it unzips it for you
Custom UI doesn't work in VR or MR mode	Currently you can use only custom UI when running the game in regular mode
Custom UI doesn't retain state upon suspend and resume	Currently there's no workaround for this issue
Exiting a world without scripts and entering one that has scripts might cause the wrong world to load	Restart Minecraft before loading a new world with scripts
Calling removeEntity on a dying entity might cause the game to crash	Don't call removeEntity the same frame you reduced the entity's damage to 0. Removing the entity forces it to be removed right away. Instead, save any dying entities and clean the up on the next frame (See the Turn-Based Demo for an example of this)

Breaking changes

While we continue to work and refine the experimental Scripting API we might need to make changes that break your current scripts. Please check this section if your scripts aren't working as expected.

Category	Change
UI	engine.on now takes a facet name. In order to check for the script engine starting and connect it to the UI you need the following: engine.on("facet:updated:core.scripting", ...); Followed by the following line after you are done doing your initialization: engine.trigger("facet:request", ["core.scripting"]);
Components	Calls to getComponent now return the component's parameters inside of the 'data' parameter of the return object.
Events	Event data objects now hold the event's parameters inside of the 'data' parameter of the event data object.
Events	Custom events need to be registered before using. Check the documentation for registerEventData for more information.
Events	Custom events need to have a namespace and can't use the 'minecraft' namespace. This namespace is reserved for built-in events only.
Events	Event Data is now standardized. Call createEventData to create an event data object prefilled with all the fields and default values for an event. You need this event data object to trigger any events.

Prerequisites

So you want to make your own Scripts? That's awesome! This section lists the minimum and recommended software you need. Note: Scripts are supported only on Windows 10 PCs. If you try to open a world with scripts on a device that doesn't support scripts, an error message appears to let you know you can't enter the world.

Software	Minimum	Recommended
Minecraft	Minecraft on your Windows 10 device	Minecraft on your Windows 10 device
Code Editor	Visual Studio Code or any plain-text editor	Visual Studio Community 2019 with the following components installed: 'JavaScript diagnostics', 'JavaScript and TypeScript language support', 'Just-In-Time debugger'
Debugger	N/A	Visual Studio Community 2019
Other	Vanilla Behavior Pack available from https://aka.ms/behaviorpacktemplate	Vanilla Behavior Pack available from https://aka.ms/behaviorpacktemplate
Storage	1.0 GB of free space for text editor, game, and scripts	3.0 GB of free space for Visual Studio, game, and scripts

Getting started

First you must download the latest Vanilla Behavior Pack. You can get this from the following link: https://aka.ms/behaviorpacktemplate

Once you have downloaded the Behavior Pack, unzip it to a folder. Inside the Behavior Pack, the scripts folder contains all the scripting files you want to run.

The scripts folder contains two folders: one for client scripts and one for server scripts.

• Server Scripts: These scripts run on the server side of the game. This includes spawning new entities, adding components, or modifying components of an entity.
• Client Scripts: These scripts run on each individual player's side of the game. This is a good place to respond to events and manage anything specific to the player.

Once you have chosen whether you are making a client or server script, simply add a new blank text file with .js extension to the appropriate folder, and open it in your preferred code editor. Then code away! You can have as many or as few JavaScript files as you want here (the name of the files doesn't matter) and they all run independently of each other!

Note: For scripts to be run by the game, you must enable Experimental Gameplay on the world on which you run scripts. This is necessary while scripting is still in beta.

When entering a world that has client scripts in it, you are prompted to accept that you wish to run scripts on your device (this appears both for local worlds as well as multiplayer worlds). Additionally, if your pack contains client scripts, you need to include a client_data module in the pack's manifest. This tells the game anything in the scripts/client folder needs to be sent over to the clients. Please refer to the Add-on Documentation page for more information on the pack's manifest contents.

Folder Structure

Example of manifest module needed for client scripts

        {
            "description": "Example client scripts module",
            "type": "client_data",
            "uuid": "c05a992e-482a-455f-898c-58bbb4975e47",
            "version": [0, 0, 1]
        }

vanilla_behavior_pack

|-scripts
|--client
|---myClientScript.js
|--server
|---myServerScript.js
|-manifest.json
|-pack_icon.png

Structure of a script

In this section you can find a quick description of the basic structure of a JavaScript script file for the Minecraft Script Engine. If you would like to learn more about JavaScript or want to follow a fundamentals tutorial, you can check the official documentation on the Mozilla Developer Network here: https://developer.mozilla.org/docs/Web/JavaScript

These are, in a way, the required parts of a script but they are by no means the only parts you can have. You can create additional methods as needed - just make sure they are called from somewhere in one of the methods below!

1. System registration

First off we need to register the system for our file. This signs up our script to be set-up either on the client or server threads of the game. Generally speaking, you choose based on whether you put the script file in the client or server folders. To do that simply call registerSystem on either the client or server and give it the version of the API you require.

Parameters

Type	Name	Description
Integer	majorVersion	This is the major version of the Minecraft Script Engine your script was designed to work with
Integer	minorVersion	This is the revision of the Minecraft Script Engine your script was designed to work with

Code examples

Client System

let sampleClientSystem = client.registerSystem(0, 0);

Server System

let sampleServerSystem = server.registerSystem(0, 0);

2. System initialization

This is the first method that gets called immediately after the system is registered. It runs as soon as the script loads at world start. You can use this to set up the environment for your script: register custom components and events, sign up event listeners, etc. This runs before the world is ready and the player has been added to it. This function should be used to initialize variables and setup event listeners. You shouldn't try to spawn or interact with any entities at this point! You should also avoid interaction with UI elements or sending messages to the chat window since this is called before the player is ready.

Code example

sampleSystem.initialize = function() {
	//register event data, register components, register queries, listen for events
};

3. System update

This method gets called once every game tick. The server and client tick at 20 times per second. This is a good place to get, check, and react to component changes.

Code example

sampleSystem.update = function() {
	//Update all the things
};

4. System shutdown

This method gets called when the Minecraft Script Engine is shutting down. For the client this is when they leave the world; for the server this is after the last player has exited the world.

Code example

sampleSystem.shutdown = function() {
	//Cleanup script only things
};

Debugging

Your script isn't working or doing what you want it to do? Fret not! We have built some debugging capabilities into the Script Engine to help you figure out what's going on with your script. If you are new to programming or want to learn more about debugging we suggest checking out the documentation about debugging with Visual Studio available here: https://docs.microsoft.com/visualstudio/debugger

There are two ways to tell what happened when something goes wrong with a script: in-game and advanced, which we describe below. You only need the game and your script to debug in-game, but you need a Windows 10 PC and Visual Studio installed for the advanced debugging.

In-game

When you run a script in the game, the Script Engine prints out error messages whenever something goes wrong. For example, if you try to get a component that the script engine doesn't know about, you get an error. To look at these messages you can open the chat screen which has all the generated error messages there; or you can open the log file that the game generated. The location of the log file varies by platform. On Windows 10 you can find the log file in %APPDATA%\..\Local\Packages\Microsoft.MinecraftUWP_8wekyb3d8bbwe\LocalState\logs

We strongly encourage you to build further debug messages and tools into your scripts while working on them. This should help you discern when something isn't working quite right. Reach out on the official Discord channel if you need additional help: https://discord.gg/Minecraft

Real-time (advanced)

If you have a Windows 10 PC with Visual Studio installed, you can attach the Visual Studio debugger and debug your script in real-time. If you installed Visual Studio with the components mentioned in the "Recommended" section of this document you should have installed and enabled the Just-In-Time Debugger. This tool pops up a message from Visual Studio whenever an exception occurs in your script and allow you to open Visual Studio on the line of your script that broke.

Additionally, you can connect to the Script Engine manually and debug your code. You can use remote debugging to connect and debug Minecraft running on another device. Please refer to the Visual Studio Debugger documentation above for instructions on how to use remote debugging.

First you need to start up Visual Studio. If this is the first time you have launched Visual Studio after installation, we suggest setting up your environment for JavaScript development and logging in to your Microsoft account when prompted. This sets up the Visual Studio interface with the most important tools you need.

Once you have Visual Studio open you should launch Minecraft. Then create a new world with Experimental Gameplay enabled and apply the Behavior Pack containing your scripts.

After creating the world go back to Visual Studio and click on the Debug menu. Then click on "Attach to Process". In the window that opens there is a search box titled Filter Process. Click on it and type Minecraft.

Once the list is narrowed down to only the instance of Minecraft running, you can verify that the Script Engine is running by looking at the Type column. This say Script and either x86 or x64.

Select the process and click on Attach to attach the debugger to the game. Now you can press the Pause button to pause the Script Engine when the next line of script code runs. This allows you to inspect the values of variables in your script and break into Visual Studio if an error occurs in your code. Warning: When you hit a breakpoint to step through code with a debugger, it is possible for a client to time out and disconnect or for the server to disconnect all players.

Script API objects

Here you can find the definition of some objects returned by the script API.

Entity JS API object

Type	Name	Entity JS API Object	Description
String	__type__		READ ONLY. This defines the type of object. Can be: "entity" or "item_entity".
String	__identifier__		READ ONLY. This is the identifier for the object in the format namespace:name. For example, if the type is entity and the object is representing a vanilla cow, the identifier would be minecraft:cow
Positive Integer	id		READ ONLY. This is the unique identifier of the entity.

Level JS API object

Type	Name	Level JS API Object	Description
String	__type__		READ ONLY. This defines the type of object. Value is: "level".
Positive Integer	level_id		READ ONLY. This is the unique identifier of the level.

Component JS API object

Type	Name	Component JS API Object	Description
String	__type__		READ ONLY. This defines the type of object. Value is: "component".
JavaScript Object	data		This is the content of the component.

Query JS API object

Type	Name	Query JS API Object	Description
String	__type__		READ ONLY. This defines the type of object. Value is: "query".
Positive Integer	query_id		READ ONLY. This is the unique identifier of the query.

ItemStack JS API object

Type	Name	ItemStack JS API Object	Description
String	__type__		READ ONLY. This defines the type of object. Value is: "item_stack".
String	__identifier__		READ ONLY. This is the identifier for the object in the format namespace:name. For example, if the type is entity and the object is representing a vanilla cow, the identifier would be minecraft:cow
String	item		READ ONLY. This is the identifier of the item.
String	count		READ ONLY. This is the number of items in the stack.

Block JS API object

Type	Name	Block JS API Object	Description
String	__type__		READ ONLY. This defines the type of object. Value is: "block".
String	__identifier__		READ ONLY. This is the identifier for the object in the format namespace:name. For example, if the type is block and the object is representing a block of bedrock, the identifier would be minecraft:bedrock
JavaScript Object	ticking_area		READ ONLY. This is the ticking area object that was used to get this block.
JavaScript Object	block_position		READ ONLY. This is the position of the block and it functions as part of its unique identifier. Parameters Type Name Description Integer x The x position Integer y The y position Integer z The z position

Ticking area JS API object

There are two types of ticking area objects. Entity and Level. When a function calls for a ticking area it can take either type as an argument.

Entity ticking area JS API object

Type	Name	Entity Ticking Area JS API Object	Description
String	__type__		READ ONLY. This defines the type of object. Value is: "entity_ticking_area".
Positive Integer	entity_ticking_area_id		READ ONLY. This is the unique identifier of the ticking area.

Level ticking area JS API object

Type	Name	Level Ticking Area JS API Object	Description
String	__type__		READ ONLY. This defines the type of object. Value is: "level_ticking_area".
String	level_ticking_area_id		READ ONLY. This is the unique identifier of the ticking area.

Script bindings

Bindings are the capabilities of the Minecraft Script Engine to change or modify things in the game.

Logging bindings

log(Message)

The log function is accessed through the server or client objects and allows for logging a message to the ContentLog file. On Windows 10 devices it is located at %APPDATA%\..\Local\Packages\Microsoft.MinecraftUWP_8wekyb3d8bbwe\LocalState\logs

Parameters 

Type	Name	Description
String	Message	The message that you want to send to the log file

Code example

Log

system.exampleFunction = function() {
	client.log("example log message") 
}; 

Entity bindings

createEntity()

Creates an empty entity with no components and does not place it in the world. The empty entity is of type "custom" and have a blank identifier. This is not a valid entity that exists in the world, just an empty one that only scripts know about.

NOTE: Entities are created first on the server, with the client notified of new entities afterwards. Be aware that if you send the result object to the client right away, the created entity might not exist on the client yet.

Return value

Type	Value	Description
Entity JS API Object	object	An object representing the newly created entity
JavaScript Object	null	Something went wrong when creating the entity

createEntity(Type, TemplateIdentifier)

Creates an entity and applies the specified template as defined in JSON. This allows you to quickly create an entity from the applied Behavior Packs as the base for an entity created in scripting. The entity gets spawned into the world with all the components, component groups, and event triggers that are defined in the JSON file of the identifier specified. Only works on scripts registered on the server. NOTE: Entities are created first on the server, with the client notified of new entities afterwards. Be aware that if you send the result object to the client right away, the created entity might not exist on the client yet.

Parameters

Type	Name	Description
String	Type	Specifies the type of the entity that is being created by the template. Valid inputs are `entity` and `item_entity`
String	TemplateIdentifier	This can be any of the entity identifiers from the applied Behavior Packs. For example, specifying minecraft:cow here makes the provided entity a cow as defined in JSON

Return value

Type	Value	Description
Entity JS API Object	object	An object representing the newly created entity
JavaScript Object	null	Something went wrong when creating the entity

destroyEntity(EntityObject)

Destroys an entity identified by the EntityObject. If the entity exists in the world this removes it from the world and destroy it. This also makes the EntityObject no longer valid - you should only destroy an entity after you are done with it and no longer need to reference it again. This does not kill the entity. There is no event for its death; it is simply removed.

Parameters

Type	Name	Description
Entity JS API Object	EntityObject	The object that was retrieved from a call to createEntity() or retrieved from an entity event

Return value

Type	Value	Description
Boolean	true	The entity was successfully destroyed
JavaScript Object	null	Something went wrong when destroying the entity

isValidEntity(EntityObject)

Checks if the given EntityObject corresponds to a valid entity.

Parameters

Type	Name	Description
Entity JS API Object	EntityObject	The object that was retrieved from a call to createEntity() or retrieved from an entity event

Return value

Type	Value	Description
Boolean	true	The entity is in the Script Engine's database of entities
Boolean	false	The entity is not in the Script Engine's database of entities
JavaScript Object	null	Something went wrong when validating the entity

Component bindings

registerComponent(ComponentIdentifier, ComponentData)

Creates a custom component that only exists in script. It can be then added, removed, and updated from entities. These custom components only exist while the Script Engine is running.

Parameters

Type	Name	Description
String	ComponentIdentifier	The identifier of the custom component. It is required to use a namespace so you can uniquely refer to it later without overlapping a name with a built-in component: for example 'myPack:myCustomComponent'
JavaScript Object	ComponentData	A JavaScript Object that defines the name of the fields and the data each field holds inside the component.

Return value

Type	Value	Description
Boolean	true	The component was successfully registered
JavaScript Object	null	Something went wrong when registering the component

createComponent(EntityObject, ComponentIdentifier)

Creates the specified component and adds it to the entity. This should only be used with custom components which need to be registered first. If the entity already has the component, this retrieves the component already there instead.

Parameters

Type	Name	Description
Entity JS API Object	EntityObject	The EntityObject that was retrieved from a call to createEntity() or retrieved from an event
String	ComponentIdentifier	The identifier of the component to add to the entity. This is either the identifier of a built-in component (check the Script Components section) or a custom component created with a call to registerComponent()

Return value

Type	Value	Description
Component JS API Object	object	An object with the following fields, and additionally, all the fields as defined in the component
JavaScript Object	null	Something went wrong when creating the component

hasComponent(EntityObject, ComponentIdentifier)

Checks if the given entity has the specified component.

Parameters

Type	Name	Description
Entity JS API Object	EntityObject	The EntityObject that was retrieved from a call to createEntity() or retrieved from an event
String	ComponentIdentifier	The identifier of the component to check on the entity. This is either the identifier of a built-in component (check the Script Components section) or a custom component created with a call to registerComponent()

Return value

Type	Value	Description
Boolean	true	The EntityObject has the component
Boolean	false	The EntityObject doesn't have the component
JavaScript Object	null	An unknown component was passed in or something else went wrong when checking if the EntityObject had the component

getComponent(EntityObject, ComponentIdentifier)

Looks for the specified component in the entity. If it exists, retrieves the data from the component and returns it.;

Parameters

Type	Name	Description
Entity JS API Object	EntityObject	The EntityObject that was retrieved from a call to createEntity() or retrieved from an event
String	ComponentIdentifier	The identifier of the component to retrieve from the entity. This is either the identifier of a built-in component (check the Script Components section) or a custom component created with a call to registerComponent()

Return value

Type	Value	Description
Component JS API Object	object	An object with the following fields, and additionally, all the fields as defined in the component Component JS API Object Type Name Component JS API Object Description String __type__ READ ONLY. This defines the type of object. Value is: "component". JavaScript Object data This is the content of the component.
JavaScript Object	null	The entity did not have the component or something went wrong when getting the component

applyComponentChanges(EntityObject, ComponentObject)

Applies the component and any changes made to it in script back to the entity. What this means for each component can be slightly different: it makes the component reload on the entity with the new data as if it had just been added to the entity.

Parameters

Type	Name	Description
Entity JS API Object	EntityObject	The entity object that we are applying the component changes to
Component JS API Object	ComponentObject	The component object retrieved from the entity that was returned by either createComponent() or getComponent()

Return value

Type	Value	Description
Boolean	true	The component was successfully updated
JavaScript Object	null	Something went wrong when updating the component

destroyComponent(EntityObject, ComponentIdentifier)

Removes the specified component from the given entity. If the entity has the component, it is removed. Currently this only works with custom components and can't be used to remove components defined for an entity in JSON.

Parameters

Type	Name	Description
Entity JS API Object	EntityObject	The EntityObject that was retrieved from a call to createEntity() or retrieved from an event
String	ComponentIdentifier	The identifier of the component to remove from the entity. This is either the identifier of a built-in component (check the Script Components section) or a custom component created with a call to registerComponent()

Return value

Type	Value	Description
Boolean	true	The component was successfully removed from the entity
JavaScript Object	null	The entity did not have the component or something went wrong when removing the component

Event bindings

These are the bindings used to handle events. For a list of events you can react to or trigger, check the Events section of this document.

registerEventData(EventIdentifier, EventData)

Registers the Event to the script engine. This allows you to create Event Data by calling createEventData and have it initialized with the correct default data and fields. Only custom events need to be registered.

Parameters

Type	Name	Description
String	EventIdentifier	This is the identifier of the custom event we are registering. The namespace is required and can't be set to minecraft.
JavaScript Object	EventData	The JavaScript object with the correct fields and default values for the event

Return value

Type	Value	Description
Boolean	true	Successfully registered the event data
JavaScript Object	null	Something went wrong when registering the event for listening

createEventData(EventIdentifier)

Creates an object with all the required fields and default data for the specified event. If the event is a custom event, it needs to have been previously registered.

Parameters

Type	Name	Description
String	EventIdentifier	This is the identifier of the custom event we are registering. The namespace is required and can't be set to minecraft.

Return value

Type	Value	Description
JavaScript Object		The object containing the event data
JavaScript Object	null	Something went wrong when registering the event for listening

listenForEvent(EventIdentifier, CallbackObject)

Allows you to register a JavaScript object that gets called whenever the specified event is broadcast. The event can either be a built-in event or an event specified in script.

Parameters

Type	Name	Description
String	EventIdentifier	This is the identifier of the event to which we want to react. Can be the identifier of a built-in event or a custom one from script
JavaScript Object	CallbackObject	The JavaScript object to be called whenever the event is broadcast

Return value

Type	Value	Description
Boolean	true	Successfully registered to listen for the event
JavaScript Object	null	Something went wrong when registering the event for listening

broadcastEvent(EventIdentifier, EventData)

Allows you to trigger an event with the desired data from script. Anything that signed up to listen for the event is notified and the given data delivered to them.

Parameters 

Type	Name	Description
String	EventIdentifier	This is the identifier of the event we want to react to. Can be the identifier of a built-in event or a custom one from script
JavaScript Object	EventData	The data for the event. You can create a new JavaScript Object with the parameters you want to pass in to the listener and the engine takes care of delivering the data to them

Return value

Type	Value	Description
Boolean	true	Successfully broadcasted the event
JavaScript Object	null	Something went wrong when broadcasting the event

Entity queries

Entity Queries are a way for you to filter for entities based on their components. Once you have registered a query, you can request all the entities that are captured by it. Entity Queries only ever return entities that are currently active in the level. If your query extends into chunks that are not currently loaded, entities there are not included in the query.

registerQuery()

Allows you to register a query. A query contains all entities that meet the filter requirement. No filters are added by default when you register a query so it captures all entities.

Return value

Type	Value	Description
Query JS API Object	object	An object containing the ID of the query
JavaScript Object	null	Something went wrong when creating the query

Code example

Query Registration

var simple_query = {};
system.initialize = function() {
	simple_query = this.registerQuery(); 
}; 

registerQuery(Component, ComponentField1, ComponentField2, ComponentField3)

Allows you to register a query that show only entities that have the given component and define which fields of that component are used as a filter when getting the entities from the query. You can either provide just the component identifier, or the component identifier and the name of 3 properties on that component to be tested (If you do specify property names, you must specify 3).

Parameters

Type	Name	Default Value	Description
String	Component		This is the identifier of the component that is used to filter entities when
String	ComponentField1	"x"	This is the name of the first field of the component that we want to filter entities by. By default this is set to x.
String	ComponentField2	"y"	This is the name of the second field of the component that we want to filter entities by. By default this is set to y.
String	ComponentField3	"z"	This is the name of the third field of the component that we want to filter entities by. By default this is set to z.

Return value

Type	Value	Description
Query JS API Object	object	An object containing the ID of the query
JavaScript Object	null	Something went wrong when creating the query

Code example

Query Registration

var spacial_query = {};
system.initialize = function() {
	spacial_query = this.registerQuery("minecraft:position", "x", "y", "z"); 
}; 

addFilterToQuery(Query, ComponentIdentifier)

By default no filters are added. This allows queries to capture all entities.

Parameters

Type	Name	Description
Query JS API Object	Query	The object containing the ID of the query that you want to apply the filter to
String	ComponentIdentifier	This is the identifier of the component that is added to the filter list. Only entities that have that component are listed in the query

Code example

Query Filtering

var filtered_query = {};
system.initialize = function() {
	filtered_query = this.registerQuery(); 
	this.addFilterToQuery(filtered_query, "minecraft:explode"); 
}; 

getEntitiesFromQuery(Query)

Allows you to fetch the entities captured by a query.<

Parameters

Type	Name	Description
Query JS API Object	Query	This is the query you registered earlier using registerQuery()

Return value

Type	Value	Description
Array	array	An array of EntityObjects representing the entities found within the query
JavaScript Object	null	Something went wrong when creating the entity

Code example

Entity Fetching

system.update = function() {
	let all_entities = this.getEntitiesFromQuery(simple_query);
	let exploding_creepers = this.getEntitiesFromQuery(filtered_query);
}; 

getEntitiesFromQuery(Query, ComponentField1_Min, ComponentField2_Min, ComponentField3_Min, ComponentField1_Max, ComponentField2_Max, ComponentField3_Max)

Allows you to fetch the entities captured by a query that was created with a component filter built-in. The only entities returned are those entities that have the component that was defined when the query was registered and that have a value in the three fields on that component that were defined in the query within the values specified in the call to getEntitiesFromQuery.

Parameters

Type	Name	Description
Query JS API Object	Query	This is the query you created earlier using registerQuery(...)
Decimal	ComponentField1_Min	The minimum value that the first component field needs to be on an entity for that entity to be included in the query
Decimal	ComponentField2_Min	The minimum value that the second component field needs to be on an entity for that entity to be included in the query
Decimal	ComponentField3_Min	The minimum value that the third component field needs to be on an entity for that entity to be included in the query
Decimal	ComponentField1_Max	The maximum value that the first component field needs to be on an entity for that entity to be included in the query
Decimal	ComponentField2_Max	The maximum value that the second component field needs to be on an entity for that entity to be included in the query
Decimal	ComponentField3_Max	The maximum value that the third component field needs to be on an entity for that entity to be included in the query

Return value

Type	Value	Description
Array	array	An array of EntityObjects representing the entities found within the query
JavaScript Object	null	Something went wrong when creating the entity

Code example

Entity Fetching

system.update = function() {
	let player_pos_component = this.getComponent(player, "minecraft:position");
	let pos = player_pos_component.data;
	let spacial_query = this.registerQuery("minecraft:position", "x", "y", "z");
	let entities_near_player = this.getEntitiesFromQuery(spacial_query, pos.x - 10, pos.y - 10, pos.z - 10, pos.x + 10, pos.y + 10, pos.z + 10);
}; 

Slash commands

You can use the traditional Slash Command system from scripts. Currently you can either trigger an event ("minecraft:execute_command") or use the executeCommand binding. Commands in scripts are restricted to server scripts, they can't be run from the client's side at the moment.

executeCommand(Command, Callback)

Allows you to execute a Slash Command on the server. The command is queried and executed at the end of the current frame. All data output from the command is compiled on a JavaScript Object and sent to the Callback object specified in the second parameter.

Parameters

Type	Name	Description
String	Command	The slash command to run
JSON Object	Callback	The JavaScript object called after the command executes

Code example

system.executeCommand("/fill ~ ~ ~ ~100 ~5 ~50 stone", (commandResultData) => this.commandCallback(commandResultData));

system.commandCallback = function (commandResultData) {
	let eventData = this.createEventData("minecraft:display_chat_event");
	if (eventData) {
		eventData.data.message = message;
		this.broadcastEvent("minecraft:display_chat_event", "Callback called! Command: " + commandResultData.command + " Data: " + JSON.stringify(commandResultData.data, null, "    ") );
	}
};

Block bindings

These functions define how you interact with blocks.

getBlock(Ticking Area, x, y, z)

Allows you to get a block from the world when provided an x, y, and z position. The block must be within a ticking area.

Parameters

Type	Name	Description
Ticking Area JS API Object	Ticking Area	The ticking area the block is in
Integer	x	The x position of the block you want
Integer	y	The y position of the block you want
Integer	z	The z position of the block you want

Return value

Type	Value	Description
Block JS API Object	object	An object containing the block
JavaScript Object	null	Something went wrong when retrieving the block

getBlock(Ticking Area, PositionObject)

Allows you to get a block from the world when provided a JavaScript object containing a position. The block must be within a ticking area.

Parameters

Type	Name	Description
Ticking Area JS API Object	Ticking Area	The ticking area the block is in
JavaScript Object	PositionObject	A JavaScript object with the x, y, and z position of the block you want Parameters Type Name Description Integer x The x position Integer y The y position Integer z The z position

Return value

Type	Value	Description
Block JS API Object	object	An object containing the block
JavaScript Object	null	Something went wrong when retrieving the block

getBlocks(Ticking Area, x min, y min, z min, x max, y max, z max)

Allows you to get an array of blocks from the world when provided a minimum and maximum x, y, and z position. The blocks must be within a ticking area.

Parameters 

Type	Name	Description
Ticking Area JS API Object	Ticking Area	The ticking area the blocks are in
Integer	x min	The minimum x position of the blocks you want
Integer	y min	The minimum y position of the blocks you want
Integer	z min	The minimum z position of the blocks you want
Integer	x max	The maximum x position of the blocks you want
Integer	y max	The maximum y position of the blocks you want
Integer	z max	The maximum z position of the blocks you want

Return value

Type	Value	Description
Array	array	A 3D array of block objects. Indexs are the blocks positions relative to the min position given
JavaScript Object	null	Something went wrong when retrieving the blocks

getBlocks(Ticking Area, Minimum PositionObject, Maximum PositionObject)

Allows you to get an array of blocks from the world when provided a minimum and maximum position. The blocks must be within a ticking area.

Parameters

Type	Name	Description
Ticking Area JS API Object	Ticking Area	The ticking area the blocks are in
JavaScript Object	Minimum PositionObject	A JavaScript object with the minimum x, y, and z position of the blocks you want Parameters Type Name Description Integer x The x position Integer y The y position Integer z The z position
JavaScript Object	Maximum PositionObject	A JavaScript object with the maximum x, y, and z position of the blocks you want Parameters Type Name Description Integer x The x position Integer y The y position Integer z The z position

Return value

Type	Value	Description
Array	array	A 3D array of block objects. Indexs are the blocks positions relative to the min position given
JavaScript Object	null	Something went wrong when retrieving the blocks

Script components

This is the documentation for the attributes, properties, and components available from the Minecraft Script Engine.

There are two kinds of components: server components and client components. We go into more detail on what they are in their respective sections below.

Components can be added, retrieved, updated, and removed from entities. They do not exist on their own. Currently only user-defined components can be added and removed from entities. A component must be in an entity in order to retrieve or update it.

Check the Script Engine Bindings section to see how to add, remove, retrieve, and update components. This section deals with the specific API of each component.

Level components

These are the components that belong to the level. They can only belong on the level object and cannot be removed from it. You can get the components and change their data through the global server object.

let levelComponent = this.getComponent(server.level, "minecraft:example_level_component");

minecraft:ticking_areas

This component gives access to the static ticking areas in the level. The component contains an array of ticking areas. The ticking areas can be accessed by name or by UUID if they were not given a name.

minecraft:weather

The weather component allows users to change the level's weather. Rain and lightning levels can be changed independently and the default weather cycle can be turned off completely.

Parameters

Type	Name	Description
Boolean	do_weather_cycle	This is the world option that determines if the vanilla weather cycle is used
Decimal	rain_level	A value between 0 and 1 that determains how heavy the rainfall is
Integer	rain_time	How long it rains, in ticks
Decimal	lightning_level	A value between 0 and 1 that determines how much lightning and thunder there is
Integer	lightning_time	How long lightning and thunder lasts, in ticks

Server components

These are the components that run on the server and are synced with all the clients (players) in the world.

As much as possible, the API of each component matches its JSON counterpart (with some differences noted).

minecraft:armor_container

This component represents the armor contents of an entity. The component contains an array of ItemStack JS API Objects representing each slot in the armor container. Note: Currently items and containers are read-only. Slots are ordered from head to feet.

// This example checks the players helmet armor slot for a specific item after the player attacks an entity.
system.listenForEvent("minecraft:player_attacked_entity", function(eventData) {
    // Get the players armor container
    let playerArmor = system.getComponent(eventData.data.player, "minecraft:armor_container");
    // Get the players helmet
    let playerHelmet = playerArmor.data[0];
    // Destroy the attacked entity if the player has a gold helmet equipped
    if (playerHelmet.item == "minecraft:golden_helmet") {
        system.destroyEntity(eventData.data.attacked_entity);
    }
});

minecraft:attack

This component controls the Attack Damage attribute from the entity. It allows you to change the current minimum and maximum values. Once the changes are applied, the current attack of the entity is reset to the minimum specified. With the minimum and maximum changed to the values specified. Any buffs or debuffs are left intact.

Parameters

Type	Name	Default Value	Description
Range [a, b]	damage		Range of the random amount of damage the melee attack deals. A negative value can heal the entity instead of hurting it Parameters Type Name Default Value Description Decimal range_min 0.0 The minimum amount of damage the entity can deal Decimal range_max 0.0 The maximum amount of damage the entity can deal

minecraft:collision_box

Controls the collision box of the entity. When changes to the component are applied the entity's collision box is immediately updated to reflect the new dimensions. WARNING: If the change of the collision box dimensions would cause the entity to be inside a block, the entity might become stuck there and start suffocating.

Parameters

Type	Name	Default Value	Description
Decimal	width	1.0	Width and Depth of the collision box in blocks. A negative value is assumed to be 0
Decimal	height	1.0	Height of the collision box in blocks. A negative value is assumed to be 0

minecraft:damage_sensor

Defines an array of damages and how the entity reacts to them - including whether the entity ignores that damage or not. Currently Minecraft triggers can't be properly serialized so any existing triggers are completely replaced when applyComponentChanges().

Parameters

Type	Name	Default Value	Description
List	on_damage		List of triggers with the events to call when taking this specific kind of damage, allows specifying filters for entity definitions and events
Boolean	deals_damage	true	If true, the damage dealt to the entity reduces its health; set to false to make the entity ignore that damage
String	cause		Type of damage that triggers this set of events

// This example causes an entity (in this case, a creeper) to start exploding when the player attacks it.
// Note: the entity must have the damage_sensor component and the associated events defined in their JSON description.
this.listenForEvent("minecraft:player_attacked_entity", function(eventData) {
	let damageSensorComponent = serverSystem.getComponent(eventData.attacked_entity, "minecraft:damage_sensor");
	damageSensorComponent.data[0].on_damage = { event:"minecraft:start_exploding", filters:[{test:"has_component", operator:"==", value:"minecraft:breathable"}] };
	serverSystem.applyComponentChanges(eventData.attacked_entity, damageSensorComponent);
});

minecraft:equipment

Defines the loot table the entity uses to defines its equipment. Once the changes are applied, the equipment is re-rolled and a new set of equipment is chosen for the entity.

Parameters

Type	Name	Default Value	Description
String	table		The file path to the equipment table, relative to the behavior pack's root
List	slot_drop_chance		A list of slots with the chance to drop an equipped item from that slot

minecraft:equippable

Defines how many and what items the entity can be equipped with.

slots

List of slots and the item that can be equipped

Parameters

Type	Name	Default Value	Description
Integer	slot	0	The slot number of this slot
List	accepted_items		The list of items that can go in this slot
String	item		Identifier of the item that can be equipped for this slot
String	interact_text		Text to be displayed when the entity can be equipped with this item when playing with Touch-screen controls
String	on_equip		Event to trigger when this entity is equipped with this item
String	on_unequip		Event to trigger when this item is removed from this entity

minecraft:explode

Controls the entity's explosion, timer until the explosion, and whether the timer is counting down or not.

Parameters

Type	Name	Default Value	Description
Range [a, b]	fuseLength	[0.0, 0.0]	The range for the random amount of time the fuse burns before exploding, a negative value means the explosion is immediate
Decimal	power	3.0	The radius of the explosion in blocks and the amount of damage the explosion deals
Decimal	maxResistance	Infinite	A block's explosion resistance is capped at this value when an explosion occurs
Boolean	fuseLit	false	If true, the fuse is already lit when this component is added to the entity
Boolean	causesFire	false	If true, blocks in the explosion radius are set on fire
Boolean	breaks_blocks	true	If true, the explosion destroys blocks in the explosion radius
Boolean	fireAffectedByGriefing	false	If true, whether the explosion causes fire is affected by the mob griefing game rule
Boolean	destroyAffectedByGriefing	false	If true, whether the explosion breaks blocks is affected by the mob griefing game rule

minecraft:hand_container

This component represents the contents of an entity's hands. The component contains an array of ItemStack JS API Objects representing each slot in the hand container. Note: Currently items and containers are read-only. Slot 0 is main-hand Slot 1 is off-hand.

// This example checks the players offhand slot for a specific item after the player attacks an entity.
system.listenForEvent("minecraft:player_attacked_entity", function(eventData) {
    // Get the players hand container
    let handContainer = system.getComponent(eventData.data.player, "minecraft:hand_container");
    // Get the players offhand item
    let offhandItem = handContainer.data[1];
    // Destroy the attacked entity if the player has a totem in their offhand
    if (offhandItem.item == "minecraft:totem") {
        system.destroyEntity(eventData.data.attacked_entity);
    }
});

minecraft:healable

Defines how the entity can be healed by the player. This doesn't control how much health the entity can have; you must use the Health component for that instead.

Parameters

Type	Name	Default Value	Description
Array	items		The array of items that can be used to heal this entity Parameters Type Name Default Value Description String item Item identifier that can be used to heal this entity Integer heal_amount 1 The amount of health this entity gains when fed this item Minecraft Filter filters The filter group that defines the conditions for using this item to heal the entity
Boolean	force_use	false	Determines if item can be used regardless of entity being at full health
Minecraft Filter	filters		The filter group that defines the conditions for this trigger

minecraft:health

Defines the current and maximum possible health of the entity. Upon applying the component back to the entity, the health changes. If it reaches 0 or below the entity dies.

Parameters

Type	Name	Default Value	Description
Integer	value	1	Current health of the entity
Integer	max	10	The maximum health the entity can heal

minecraft:hotbar_container

This component represents the hotbar contents of a player. The component contains an array of ItemStack JS API Objects representing each slot in the hotbar. Note: Currently items and containers are read-only. Slots are ordered left to right.

// This example check sthe players first hotbar item slot for a specific item after the player attacks an entity.
system.listenForEvent("minecraft:player_attacked_entity", function(eventData) {
    // Get the players hotbar
    let playerHotbar = system.getComponent(eventData.data.player, "minecraft:hotbar_container");
    // Get the item at the first slot in the hotbar
    let firstHotbarSlot = playerHotbar.data[0];
    // Destroy the attacked entity if the player has an apple in their first hotbar slot
    if (firstHotbarSlot.item == "minecraft:apple") {
        system.destroyEntity(eventData.data.attacked_entity);
    }
});

minecraft:interact

Defines the ways the player can interact with the entity to which this component is applied.

Parameters

Type	Name	Default Value	Description
Array	spawn_entities		An array of entity identifiers to spawn when the interaction occurs
String	on_interact		An event identifier to fire when the interaction occurs
JSON Object	particle_on_start		Particle effect to be triggered at the start of the interaction Parameters Type Name Default Value Description String particle_type The type of particle to be spawned Decimal particle_y_offset 0.0 Offsets the particle this amount in the y direction Boolean particle_offset_towards_interactor false Whether or not the particle appears closer to who performed the interaction
Decimal	cooldown	0.0	Time in seconds before this entity can be interacted with again
Boolean	swing	false	If true, the player does the 'swing' animation when interacting with this entity
Boolean	use_item	false	If true, the interaction uses an item
Integer	hurt_item	0	The amount of damage the item takes when used to interact with this entity. A value of 0 means the item does not lose durability
String	interact_text		Text to show when the player is able to interact in this way with this entity when playing with Touch-screen controls
JSON Object	add_items		Loot table with items to add to the player's inventory upon successful interaction Parameters Type Name Default Value Description String table File path, relative to the behavior pack's path, to the loot table file
JSON Object	spawn_items		Loot table with items to drop on the ground upon successful interaction Parameters Type Name Default Value Description String table File path, relative to the behavior pack's path, to the loot table file
String	transform_to_item		The item used transforms to this item upon successful interaction. Format: itemName:auxValue
Array	play_sounds		An array of sound identifiers to play when the interaction occurs

minecraft:inventory

Defines the entity's inventory (size, restrictions, etc.). Currently this does not allow changing the entity's inventory contents.

Parameters

Type	Name	Default Value	Description
String	container_type	none	Type of container this entity has. Can be horse, minecart_chest, minecart_hopper, inventory, container or hopper
Integer	inventory_size	5	Number of slots the container has
Boolean	can_be_siphoned_from	false	If true, the contents of this inventory can be removed by a hopper
Boolean	private	false	If true, only the entity can access the inventory
Boolean	restrict_to_owner	false	If true, the entity's inventory can only be accessed by its owner or itself
Integer	additional_slots_per_strength	0	Number of slots that this entity can gain per extra strength

minecraft:inventory_container

This component represents the inventory contents of an entity. The component contains an array of ItemStack JS API Objects representing each slot in the inventory. Note: Currently items and containers are read-only.Slot 0-8 is the hotbar, 9-17 is the top row of the player's inventory, 18-26 is the middle row, 27-35 is the bottom row.

// This example checks the players third inventory item slot for a specific item after the player attacks an entity.
system.listenForEvent("minecraft:player_attacked_entity", function(eventData) {
    // Get the players inventory
    let playerInventory = system.getComponent(eventData.data.player, "minecraft:inventory_container");
    // Get the item at the third slot in the inventory
    let thirdItemSlot = playerInventory.data[2];
    // Destroy the attacked entity if the player has an apple in their third item slot
    if (thirdItemSlot.item == "minecraft:apple") {
        system.destroyEntity(eventData.data.attacked_entity);
    }
});

minecraft:lookat

Makes the entity look at another entity. Once applied, if an entity of the specified type is nearby and can be targeted the entity turns toward it.

Parameters

Type	Name	Default Value	Description
Boolean	setTarget	true	If true, this entity sets the attack target as the entity that looked at it
Decimal	searchRadius	10.0	Maximum distance this entity can look for another entity looking at it
Boolean	mAllowInvulnerable	false	If true, invulnerable entities (e.g. Players in creative mode) are considered valid targets
Range [a, b]	look_cooldown	[0.0, 0.0]	The range for the random amount of time during which the entity is 'cooling down' and won't get angered or look for a target
Minecraft Filter	filters	player	Defines the entities that can trigger this component
String	look_event		The event identifier to run when the entities specified in filters look at this entity

minecraft:nameable

Nameable component describes an entity's ability to be named using a nametag and whether the name shows up or not once applied. Additionally, scripting allows setting the name of the entity directly with the property 'name'.

Parameters

Type	Name	Default Value	Description
JSON Object	name_actions		Describes the special names for this entity and the events to call when the entity acquires those names Parameters Type Name Default Value Description String on_named Event to be called when this entity acquires the name specified in 'name_filter' List name_filter List of special names that cause the events defined in 'on_named' to fire
String	default_trigger		Trigger to run when the entity gets named
Boolean	alwaysShow	false	If true, the name is always be shown
Boolean	allowNameTagRenaming	true	If true, this entity can be renamed with name tags
String	name		The current name of the entity, empty if the entity hasn't been named yet, making this non-empty applies the name to the entity

minecraft:position

This component allows you to control an entity's current position in the world. Once applied, the entity is teleported to the new position specified.

Parameters

Type	Name	Default Value	Description
Decimal	x	0.0	Position along the X-Axis (east-west) of the entity
Decimal	y	0.0	Position along the Y-Axis (height) of the entity
Decimal	z	0.0	Position along the Z-Axis (north-south) of the entity

minecraft:rotation

This component allows you to control an entity's current rotation in the world as well as the entity's head rotation. Once applied, the entity is rotated as specified.

Parameters

Type	Name	Default Value	Description
Decimal	x	0.0	Controls the head rotation looking up and down
Decimal	y	0.0	Controls the body rotation parallel to the floor

minecraft:shooter

Defines the entity's ranged attacks. This doesn't allow the entity to use a ranged attack: it only defines what kind of projectile it shoots.

Parameters

Type	Name	Default Value	Description
String	def		Entity identifier to use as projectile for the ranged attack. The entity must have the projectile component to be able to be shot as a projectile
Integer	auxVal	-1	ID of the Potion effect to be applied on hit

minecraft:spawn_entity

Controls the entity's ability to spawn an entity or an item. This is similar to the chicken's ability to lay eggs after a set amount of time.

Parameters

Type	Name	Default Value	Description
Boolean	should_leash	false	If true, this the spawned entity is leashed to the parent
Integer	num_to_spawn	10	The number of entities of this type to spawn each time that this triggers
Integer	min_wait_time	300	Minimum amount of time to randomly wait in seconds before another entity is spawned
Integer	max_wait_time	600	Maximum amount of time to randomly wait in seconds before another entity is spawned
String	spawn_sound	plop	Identifier of the sound effect to play when the entity is spawned
String	spawn_item	egg	Item identifier of the item to spawn
String	spawn_entity		Identifier of the entity to spawn, leave empty to spawn the item defined above instead
String	spawn_method	born	Method to use to spawn the entity
String	spawn_event	minecraft:entity_born	Event to call when the entity is spawned
Minecraft Filter	filters		If present, the specified entity spawns only if the filter evaluates to true
Boolean	single_use	false	If true, this component spawns the specified entity only once

minecraft:teleport

This controls the entity's ability to teleport itself (similar to the Enderman). If you wish to teleport the entity once use the Position component instead.

Parameters

Type	Name	Default Value	Description
Boolean	randomTeleports	true	If true, the entity teleports randomly
Decimal	minRandomTeleportTime	0.0	Minimum amount of time in seconds between random teleports
Decimal	maxRandomTeleportTime	20.0	Maximum amount of time in seconds between random teleports
Vector [a, b, c]	randomTeleportCube	[32.0, 16.0, 32.0]	Entity teleports to a random position within the area defined by this cube
Decimal	targetDistance	16.0	Maximum distance the entity can teleport when chasing a target
Decimal	target_teleport_chance	1.0	The chance (0.0 to 1.0, where 1.0=100%) that the entity can teleport
Decimal	lightTeleportChance	0.01	Modifies the chance that the entity can teleport if the entity is in daylight
Decimal	darkTeleportChance	0.01	Modifies the chance that the entity can teleport if the entity is in darkness

minecraft:tick_world

The tick world component is a read-only component that allows users to access the ticking areas on entities as well as the ticking area's data.

Parameters

Type	Name	Description
Integer	radius	The radius in chunks of the ticking area
Decimal	distance_to_players	distance_to_players
Boolean	never_despawn	Whether or not this ticking area despawns when a player is out of range
Entity Ticking Area JS API Object	ticking_area	The ticking area entity that is attached to this entity

Client components

These components only run on the client where the script ran and can only be used from client scripts.

minecraft:molang

The MoLang component gives access to the MoLang variables in an entity. To learn more about MoLang varibles review the add-on documentation. In scripts, you can get and set these varibles that are defined in the entity's JSON files. Because of how the MoLang variables are formatted (variable.isgrazing for example) you must use the [] operator on the object to access the variable. The example below shows how to use the [] operator to access the variable.

Code example

let molangComponent = this.createComponent(entity, "minecraft:molang"); 
molangComponent["variable.molangexample"] = 1.0; 
this.applyComponentChanges(molangComponent); 

Block components

These components are only found on block objects and can only be on block objects

minecraft:blockstate

This component contains all the blockstates on a block object. Blockstates control all different aspects of blocks from their orientation to the type of wood they are. Blockstates are represented by numbers, bools, or strings. Please see the Blockstates Documentation to see the valid values for each state. This component allows for the getting and setting of these states.

Code example

let blockstateComponent = this.getComponent(block, "minecraft:blockstate");
blockstateComponent.data.coral_color = "blue";
this.applyComponentChanges(block, blockstateComponent);

User-Defined Components

User-Defined components are a special kind of component that can be defined in script and no built-in game system acts on it. The component needs to be registered with the Script Engine by giving it a name and a set of fields in the format name:value. Once applied, the component behaves like any of the built-in components: you can get it from an entity, modify its values, and apply the changes. Currently, user-Defined components are the only components that can be dynamically added and removed from an entity using scripts. They don't need to be previously defined in an entity's JSON file. In the current version, these components are not saved out or loaded back in: they exist only while the entity is there and need to be added back when reloading the level.

Code example

Component Registration

this.registerComponent("myNamespace:myComponent", { myString: "TamerJeison", myInt: 42, myFloat: 1.0, myArray: [1, 2, 3] });

Script events

Here you can find the list of events that you can listen for and respond to in your scripts.

Client events

Listening events

The following Minecraft events are events the Script Engine is listening for and to which you can react in scripts.

minecraft:client_entered_world

This event is fired whenever a player joins the world. The event data contains the player entity object.

Parameters

Type	Name	Description
Entity JS API Object	player	The player entity that joined the world

minecraft:hit_result_changed

This event is triggered whenever the reticle changes from pointing at a block or air to pointing at an entity and the other way around. Up to 1000 blocks away.

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity that was hit or null if it fired when moving off of an entity
Vector [a, b, c]	position	The position of the entity that was hit or null if it fired when moving off an entity

Code example

system.initialize = function() {
	this.listenForEvent("minecraft:hit_result_changed", (eventData) => this.onPick(eventData)); 
}; 

system.onPick = function(eventData) { 
	if (eventData.position !== null) { 
		this.broadcastEvent("minecraft:display_chat_event", "Pick at x:" + eventData.position.x + " y:" + eventData.position.y + " z:" + eventData.position.z); 
	} 
};

minecraft:hit_result_continuous

This event is triggered every update and tells you what entity the reticle is pointing to in the world up to 1000 blocks away.

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity that was hit or null if it not pointing at an entity
Vector [a, b, c]	position	The position of the entity that was hit or block that was hit

Code example

system.initialize = function() {
	this.listenForEvent("minecraft:hit_result_continuous", (eventData) => this.onPick(eventData)); 
}; 

system.onPick = function(eventData) { 
	if (eventData.position !== null) { 
		this.broadcastEvent("minecraft:display_chat_event", "Pick at x:" + eventData.position.x + " y:" + eventData.position.y + " z:" + eventData.position.z); 
	} 
};

minecraft:pick_hit_result_changed

This event is triggered whenever the mouse pointer changes from pointing at a block or air to pointing at an entity and the other way around. Up to 1000 blocks away.

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity that was hit or null if it fired when moving off of an entity
Vector [a, b, c]	position	The position of the entity that was hit or null if it fired when moving off an entity

Code example

system.initialize = function() {
	this.listenForEvent("minecraft:pick_hit_result_changed", (eventData) => this.onPick(eventData)); 
}; 

system.onPick = function(eventData) { 
	if (eventData.position !== null) { 
		this.broadcastEvent("minecraft:display_chat_event", "Pick at x:" + eventData.position.x + " y:" + eventData.position.y + " z:" + eventData.position.z); 
	} 
};

minecraft:pick_hit_result_continuous

This event is triggered every update and tells you what entity the mouse pointer is pointing to in the world up to 1000 blocks away.

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity that was hit or null if it not pointing at an entity
Vector [a, b, c]	position	The position of the entity that was hit or block that was hit

Code example

system.initialize = function() {
	this.listenForEvent("minecraft:pick_hit_result_continuous", (eventData) => this.onPick(eventData)); 
}; 

system.onPick = function(eventData) { 
	if (eventData.position !== null) { 
		this.broadcastEvent("minecraft:display_chat_event", "Pick at x:" + eventData.position.x + " y:" + eventData.position.y + " z:" + eventData.position.z); 
	} 
};

Triggerable events

The following Minecraft Events can be triggered from scripting and cause the game to respond accordingly.

minecraft:display_chat_event

This event is used to display a chat message to the specific player that is running the client script. The event data is the message to be displayed in plain text. Special formatting is supported the same way it would be if a player was sending the message.

Parameters

Type	Name	Default Value	Description
String	message		The chat message to be displayed

minecraft:load_ui

This event is used to show a UI screen to the specific player running the client script. This event adds the UI screen to the top of the UI screen stack. The screen is shown immediately after the event is triggered. Only screens defined in a HTML file can be shown using this event.

Event Data Parameters

Type	Name	Default Value	Description
String	path		The file path to the screen's HTML file
JSON Object	options		You can define the following options for the screen by setting their value to true or false: always_accepts_input If true, the screen always accepts and processes input for as long as it is in the stack, even if other custom UI screens appear on top of it render_game_behind If true, the game continues to be rendered underneath this screen absorbs_input If true, input does pass down to any other screens underneath is_showing_menu If true, the screen is treated as the pause menu and the pause menu won't be allowed to show on top of this screen should_steal_mouse If true, the screen captures the mouse pointer and limits its movement to the UI screen force_render_below If true, this screen is rendered even if another screen is on top of it and renders over them, including the HUD render_only_when_topmost If true, this screen is rendered only if it is the screen at the top of the stack

minecraft:send_ui_event

This event is used to send UI events to the UI Engine for the specific player running the script. After the event is triggered, the UI event is sent immediately. Custom UI is based on HTML 5. Review the scripting demo for an example of a custom UI file.

Parameters

Type	Name	Description
String	eventIdentifier	The identifier of the UI event
String	data	The data for the UI event being triggered

minecraft:spawn_particle_attached_entity

This event is used to create a particle effect that follows an entity around. This particle effect is only visible to the specific player that is running the client script where you fired the event. Any effect defined in a JSON file (both in your resource pack and in Minecraft) can be used here. MoLang variables defined in the JSON of the effect can then be used to control that effect by changing them in the entity to which it is attached.

Parameters

Type	Name	Default Value	Description
String	effect		The identifier of the particle effect you want to attach to the entity. This is the same name you gave the effect in its JSON file
Vector [a, b, c]	offset	[0, 0, 0]	The offset from the entity's "center" where you want to spawn the effect
Entity JS API Object	entity		The entity object you want to attach the effect to

minecraft:spawn_particle_in_world

This event is used to create a static particle effect in the world. This particle effect is only visible to the specific player that is running the client script where you fired the event. Any effect defined in a JSON file (both in your resource pack and in Minecraft) can be used here. Once the effect is spawned you won't be able to control it further. Unlike the server version of the event, the client version spawns the particle in the dimension the player is currently in.

Parameters

Type	Name	Default Value	Description
String	effect		The identifier of the particle effect you want to attach to spawn. This is the same name you gave the effect in its JSON file
Vector [a, b, c]	position	[0, 0, 0]	The position in the world where you want to spawn the effect

minecraft:unload_ui

This event is used to remove a UI screen from the stack of the specific player running the client script. The event data contains the name of the screen to remove as a string. After the event is triggered, the screen is scheduled to be removed from the stack the next time the UI Engine can do so. Only screens defined in a HTML file can be removed using this event.

minecraft:script_logger_config

This event is used to turn various levels of logging on and off for client scripts. Note that turning logging on/off is not limited to the script that broadcasted the event. It affects all client scripts including those in other Behavior Packs that are applied to the world. See the Debugging section for more information on logging.

Parameters

Type	Name	Default Value	Description
Boolean	log_errors	false	Set to true to log any scripting errors that occur on the client
Boolean	log_warnings	false	Set to true to log any scripting warnings that occur on the client
Boolean	log_information	false	Set to true to log any general scripting information that occurs on the client. This includes any logging done with client.log()

Server events

Listening events

The following Minecraft events are events the Script Engine is listening for and to which you can react in scripts.

minecraft:player_attacked_entity

This event is triggered whenever a player attacks an entity.

Parameters

Type	Name	Description
Entity JS API Object	player	The player that attacked an entity
Entity JS API Object	attacked_entity	The entity that was attacked by the player

minecraft:entity_acquired_item

This event is triggered whenever an entity acquires an item.

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity who acquired the item
ItemStack JS API Object	item_stack	The item that was acquired
String	acquisition_method	The way the entity acquired the item
Integer	acquired_amount	The total number of items acquired by the entity during this event
Entity JS API Object	secondary_entity	If it exists, the entity that affected the item before it was acquired. Example: A player completes a trade with a villager. The `entity` property would be the player and the `secondary_entity` would be the villager

minecraft:entity_carried_item_changed

This event is triggered whenever an entity changes the item carried in their hand.

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity that changed what they were carrying
ItemStack JS API Object	previous_carried_item	The item that was previously in the entities hands
ItemStack JS API Object	carried_item	The item that is now in the entities hands

minecraft:entity_created

This event is triggered whenever an entity is added to the world.

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity that was just created

minecraft:entity_death

This event is triggered whenever an entity dies. This won't be triggered when an entity is removed (such as when using destroyEntity).

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity that died

minecraft:entity_dropped_item

This event is triggered whenever an entity drops an item.

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity who dropped the item
ItemStack JS API Object	item_stack	The item that was dropped

minecraft:entity_equipped_armor

This event is triggered whenever an entity equips an item in their armor slots.

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity who is equipping the armor
ItemStack JS API Object	item_stack	The armor that is being equipped

minecraft:entity_start_riding

This event is triggered whenever an entity becomes a rider on another entity.

Parameters

Type	Name	Description
Entity JS API Object	entity	The rider
Entity JS API Object	ride	The entity being ridden

minecraft:entity_stop_riding

This event is triggered whenever an entity stops riding another entity.

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity that was riding another entity
Boolean	exit_from_rider	If true, the rider stopped riding by their own decision
Boolean	entity_is_being_destroyed	If true, the rider stopped riding because they are now dead
Boolean	switching_rides	If true, the rider stopped riding because they are now riding a different entity

minecraft:entity_tick

This event is triggered whenever an entity is ticked. This event does not fire when a player is ticked.

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity that was ticked

minecraft:entity_use_item

This event is triggered whenever an entity uses an item.

Parameters

Type	Name	Description
Entity JS API Object	entity	The entity who is using the item
ItemStack JS API Object	item_stack	The item that is being used
String	use_method	The way the entity used the item

minecraft:block_destruction_started

This event is triggered whenever a player starts to destroy a block.

Parameters

Type	Name	Description
Entity JS API Object	player	The player that started destoying the block
JavaScript Object	block_position	The position of the block that is being destroyed

minecraft:block_destruction_stopped

This event is triggered whenever a player stops destroying a block.

Parameters

Type	Name	Description
Entity JS API Object	player	The player that stopped destoying the block
JavaScript Object	block_position	The position of the block that was being destroyed
Decimal	destruction_progress	How far along the destruction was before it was stopped (0 - 1 range)

minecraft:block_interacted_with

This event is triggered whenever a player interacts with a block.

Parameters

Type	Name	Description
Entity JS API Object	player	The player that interacted with the block
JavaScript Object	block_position	The position of the block that is being interacted with

minecraft:piston_moved_block

This event is triggered whenever a piston moves a block.

Parameters

Type	Name	Description
JavaScript Object	piston_position	The position of the piston that moved the block
JavaScript Object	block_position	The position of the block that was moved
String	piston_action	The action the piston took, "extended" or "retracted"

minecraft:player_destroyed_block

This event is triggered whenever a player destroys a block.

Parameters

Type	Name	Description
Entity JS API Object	player	The player that destroyed the block
JavaScript Object	block_position	The position of the block that was destroyed
String	block_identifier	The identifier of the block that was destroyed

minecraft:player_placed_block

This event is triggered whenever a player places a block.

Parameters

Type	Name	Description
Entity JS API Object	player	The player that placed the block
JavaScript Object	block_position	The position of the block that was placed

minecraft:play_sound

This event is used to play a sound effect. Currently, sounds can only be played at a fixed position in the world. Global sounds and sounds played by an entity may be supported in a later update.

Parameters

Type	Name	Default Value	Description
String	sound		The identifier of the sound you want to play. Only sounds defined in the applied resource packs can be played
Decimal	volume	1.0	The volume of the sound effect. A value of 1.0 plays the sound effect at the volume it was recorded at
Decimal	pitch	1.0	The pitch of the sound effect. A value of 1.0 plays the sound effect with regular pitch
Vector [a, b, c]	position	[0, 0, 0]	The position in the world we want to play the sound at

minecraft:weather_changed

This event is triggered whenever the weather changes. It contains information about the weather it is changing to.

Parameters

Type	Name	Description
String	dimension	The name of the dimension where the weather change happened
Boolean	raining	Tells if the new weather has rain
Boolean	lightning	Tells if the new weather has lightning

Triggerable events

The following Minecraft events can be triggered from scripting and the game responds accordingly.

minecraft:display_chat_event

This event is used to send a chat message from the server to the players. The event data is the message being sent as a string. Special formatting is supported the same way it would be if a player was sending the message.

Parameters

Type	Name	Default Value	Description
String	message		The chat message to be displayed

minecraft:execute_command

This event is used to execute a slash command on the server with the World Owner permission level. The event data contains the slash command as a string. The slash command is processed and runs after the event is sent.

Parameters

Type	Name	Default Value	Description
String	command		The command to be run

minecraft:play_sound

This event is used to play a sound effect. Currently, sounds can only be played at a fixed position in the world. Global sounds and sounds played by an entity may be supported in a later update.

Parameters

Type	Name	Default Value	Description
String	sound		The identifier of the sound you want to play. Only sounds defined in the applied resource packs can be played
Decimal	volume	1.0	The volume of the sound effect. A value of 1.0 plays the sound effect at the volume it was recorded at
Decimal	pitch	1.0	The pitch of the sound effect. A value of 1.0 plays the sound effect with regular pitch
Vector [a, b, c]	position	[0, 0, 0]	The position in the world we want to play the sound at

minecraft:spawn_particle_attached_entity

This event is used to create a particle effect that follows an entity around. This particle effect is visible to all players. Any effect defined in a JSON file (both in your resource pack and in Minecraft) can be used here. MoLang variables defined in the JSON of the effect can then be used to control that effect by changing them in the entity to which it is attached.

Parameters

Type	Name	Default Value	Description
String	effect		The identifier of the particle effect you want to attach to the entity. This is the same identifier you gave the effect in its JSON file
Vector [a, b, c]	offset	[0, 0, 0]	The offset from the entity's "center" where you want to spawn the effect
Entity JS API Object	entity		The entity object you want to attach the effect to

minecraft:spawn_particle_in_world

This event is used to create a static particle effect in the world. This particle effect is visible to all players. Any effect defined in a JSON file (both in your resource pack and in Minecraft) can be used here. Once the effect is spawned you won't be able to control it further.

Parameters

Type	Name	Default Value	Description
String	effect		The identifier of the particle effect you want to attach to spawn. This is the same name you gave the effect in its JSON file
Vector [a, b, c]	position	[0, 0, 0]	The position in the world where you want to spawn the effect
String	dimension	overworld	The dimension in which you want to spawn the effect. Can be "overworld", "nether", or "the end"

minecraft:script_logger_config

This event is used to turn various levels of logging on and off for server scripts. Note that turning logging on/off is not limited to the script that broadcasted the event. It affects all server scripts including those in other Behavior Packs that are applied to the world. See the Debugging section for more information on logging.

Parameters

Type	Name	Default Value	Description
Boolean	log_errors	false	Set to true to log any scripting errors that occur on the server
Boolean	log_warnings	false	Set to true to log any scripting warnings that occur on the server
Boolean	log_information	false	Set to true to log any general scripting information that occurs on the server. This includes any logging done with server.log()

See also

• Add-on
• Bedrock Edition creator guidelines
• Bedrock Edition add-on documentation
• Bedrock Edition entity components documentation
• Bedrock Edition entity events documentation
• Bedrock Edition animation documentation
• Bedrock Edition particle documentation
• Bedrock Edition MoLang documentation
• Bedrock Edition UI documentation
• Bedrock Edition schemas documentation