State Synchronization » Schema¶

Not using TypeScript yet?

It is highly recommended that you use TypeScript to have a better experience defining the schemas structures, and for your development experience in general. TypeScript supports the "experimental decorators" that is heavily used on this section.

How to define synchronizable structures¶

Schema structures are defined the server-side to be used in the room state.
Only fields decorated with @type() are going to be considered for synchronization.
(Synchronizable schema structures should only be used for data related to your state.)

Defining a `Schema` structure¶

TypeScript

// MyState.ts
import { Schema, type } from "@colyseus/schema";

export class MyState extends Schema {
    @type("string") currentTurn: string;
}

JavaScript

// MyState.ts
const schema = require('@colyseus/schema');
const Schema = schema.Schema;

class MyState extends Schema {
}
schema.defineTypes(MyState, {
  currentTurn: "string"
});

"What is this @type() keyword? I've never seen this before!"

The @type() you see heavily used on this page is an upcoming JavaScript feature that is yet to be formally established by TC39. type is actually just a function imported from @colyseus/schema module. By calling type with the @ prefix at the property level means we're calling it as a property decorator. See the decorators proposal here.

Using the state within your `Room`¶

// MyRoom.ts
import { Room } from "colyseus";
import { MyState } from "./MyState";

export class MyRoom extends Room<MyState> {
    onCreate() {
        this.setState(new MyState());
    }
}

Working with schemas¶

Only the server-side is responsible for mutating schema structures
The client-side must have the same Schema definitions generated through schema-codegen. (Optional if you're using the JavaScript SDK)
In order to get updates from the server, you need to attach callbacks on schema instances in the client-side.
The client-side should never perform mutations on schema - as they are going to be replaced as soon as the next change come from the server.

Primitive types¶

Primitive types are numbers, strings and boolean.

Type	Description	Limitation
`"string"`	utf8 strings	maximum byte size of `4294967295`
`"number"`	also known as "varint". Auto-detects the number type to use. (may use one extra byte when encoding)	`0` to `18446744073709551615`
`"boolean"`	`true` or `false`	`0` or `1`

Specialized number types:

Type	Description	Limitation
`"int8"`	signed 8-bit integer	`-128` to `127`
`"uint8"`	unsigned 8-bit integer	`0` to `255`
`"int16"`	signed 16-bit integer	`-32768` to `32767`
`"uint16"`	unsigned 16-bit integer	`0` to `65535`
`"int32"`	signed 32-bit integer	`-2147483648` to `2147483647`
`"uint32"`	unsigned 32-bit integer	`0` to `4294967295`
`"int64"`	signed 64-bit integer	`-9223372036854775808` to `9223372036854775807`
`"uint64"`	unsigned 64-bit integer	`0` to `18446744073709551615`
`"float32"`	single-precision floating-point number	`-3.40282347e+38` to `3.40282347e+38`
`"float64"`	double-precision floating-point number	`-1.7976931348623157e+308` to `1.7976931348623157e+308`

Complex types¶

Complex types consist of Schema instances within other schema instances. They can also contain collections of items (array, map, etc.).

TypeScript

import { Schema, type } from "@colyseus/schema";

class World extends Schema {
    @type("number") width: number;
    @type("number") height: number;
    @type("number") items: number = 10;
}

class MyState extends Schema {
    @type(World) world: World = new World();
}

JavaScript

const schema = require('@colyseus/schema');
const Schema = schema.Schema;

class World extends Schema {
}
schema.defineTypes(World, {
  width: "number",
  height: "number",
  items: "number"
});

class MyState extends Schema {
    constructor () {
        super();

        this.world = new World();
    }
}
schema.defineTypes(MyState, {
  world: World
});

Collections of items¶

ArraySchema¶

The ArraySchema is a synchronizeable version of the built-in JavaScript Array type.

Example: Array of custom Schema type

TypeScript

import { Schema, ArraySchema, type } from "@colyseus/schema";

class Block extends Schema {
    @type("number") x: number;
    @type("number") y: number;
}

class MyState extends Schema {
    @type([ Block ]) blocks = new ArraySchema<Block>();
}

JavaScript

const schema = require('@colyseus/schema');
const Schema = schema.Schema;
const ArraySchema = schema.ArraySchema;

class Block extends Schema {
}
schema.defineTypes(Block, {
  x: "number",
  y: "number"
});

class MyState extends Schema {
    constructor () {
        super();

        this.blocks = new ArraySchema();
    }
}
schema.defineTypes(MyState, {
  blocks: [ Block ],
});

Example: Array of a primitive type

You can't mix types inside arrays.

TypeScript

import { Schema, ArraySchema, type } from "@colyseus/schema";

class MyState extends Schema {
    @type([ "string" ]) animals = new ArraySchema<string>();
}

JavaScript

const schema = require('@colyseus/schema');
const Schema = schema.Schema;
const ArraySchema = schema.ArraySchema;

class MyState extends Schema {
    constructor () {
        super();

        this.animals = new ArraySchema();
    }
}
schema.defineTypes(MyState, {
  animals: [ "string" ],
});

`array.push()`¶

Adds one or more elements to the end of an array and returns the new length of the array.

const animals = new ArraySchema<string>();
animals.push("pigs", "goats");
animals.push("sheeps");
animals.push("cows");
// output: 4

`array.pop()`¶

Removes the last element from an array and returns that element. This method changes the length of the array.

animals.pop();
// output: "cows"

animals.length
// output: 3

`array.shift()`¶

Removes the first element from an array and returns that removed element. This method changes the length of the array.

animals.shift();
// output: "pigs"

animals.length
// output: 2

`array.unshift()`¶

Adds one or more elements to the beginning of an array and returns the new length of the array.

animals.unshift("pigeon");
// output: 3

`array.indexOf()`¶

Returns the first index at which a given element can be found in the array, or -1 if it is not present

const itemIndex = animals.indexOf("sheeps");

`array.splice()`¶

Changes the contents of an array by removing or replacing existing elements and/or adding new elements in place.

// find the index of the item you'd like to remove
const itemIndex = animals.findIndex((animal) => animal === "sheeps");

// remove it!
animals.splice(itemIndex, 1);

`array.forEach()`¶

Iterates over each element of the array.

TypeScript

this.state.array1 = new ArraySchema<string>('a', 'b', 'c');

this.state.array1.forEach(element => {
    console.log(element);
});
// output: "a"
// output: "b"
// output: "c"

C#

State.array1.ForEach((value) => {
    Debug.Log(value);
})

LUA

state.array1:each(function(value, index)
    print(index, "=>")
    pprint(value)
end)

Haxe

for (index => value in state.array1) {
    trace(index + " => " + value);
}

More methods available for Array

Have a look at the MDN Documentation.

MapSchema¶

The MapSchema is a synchronizeable version of the built-in JavaScript Map type.

Maps are recommended to track your game entities by id, such as players, enemies, etc.

Only string keys are supported at the moment

Currently, the MapSchema only allows you to customize the value type. The key type is always string.

TypeScript

import { Schema, MapSchema, type } from "@colyseus/schema";

class Player extends Schema {
    @type("number") x: number;
    @type("number") y: number;
}

class MyState extends Schema {
    @type({ map: Player }) players = new MapSchema<Player>();
}

JavaScript

const schema = require('@colyseus/schema');
const Schema = schema.Schema;
const MapSchema = schema.MapSchema;

class Player extends Schema {
}
schema.defineTypes(Player, {
  x: "number",
  y: "number"
});

class MyState extends Schema {
    constructor () {
        super();

        this.players = new MapSchema();
    }
}
schema.defineTypes(MyState, {
  players: { map: Player }
});

`map.get()`¶

Getting a map item by its key:

const map = new MapSchema<string>();
const item = map.get("key");

OR

//
// NOT RECOMMENDED
//
// This is a compatibility layer with previous versions of @colyseus/schema
// This is going to be deprecated in the future.
//
const item = map["key"];

`map.set()`¶

Setting a map item by key:

const map = new MapSchema<string>();
map.set("key", "value");

OR

//
// NOT RECOMMENDED
//
// This is a compatibility layer with previous versions of @colyseus/schema
// This is going to be deprecated in the future.
//
map["key"] = "value";

`map.delete()`¶

Removes a map item by key:

map.delete("key");

OR

//
// NOT RECOMMENDED
//
// This is a compatibility layer with previous versions of @colyseus/schema
// This is going to be deprecated in the future.
//
delete map["key"];

`map.size`¶

Return the number of elements in a MapSchema object.

const map = new MapSchema<number>();
map.set("one", 1);
map.set("two", 2);

console.log(map.size);
// output: 2

`map.forEach()`¶

Iterates over each key/value pair of the map, in insertion order.

TypeScript

this.state.players.forEach((value, key) => {
    console.log("key =>", key)
    console.log("value =>", value)
});

C#

State.players.ForEach((key, value) => {
    Debug.Log(key);
    Debug.Log(value);
})

LUA

state.players:each(function(value, key)
    print(key, "=>")
    pprint(value)
end)

Haxe

for (key => value in state.players) {
    trace(index + " => " + value);
}

More methods available for Map

Have a look at the MDN Documentation.

SetSchema¶

SetSchema is only implemented in JavaScript

The SetSchema can only be used with JavaScript so far. Haxe, C#, LUA and C++ clients are not supported yet.

The SetSchema is a synchronizeable version of the built-in JavaScript Set type.

The usage of SetSchema is very similar to [CollectionSchema], the biggest difference is that Sets hold unique values. Sets do not have a way to access a value directly. (like collection.at())

TypeScript

import { Schema, SetSchema, type } from "@colyseus/schema";

class Effect extends Schema {
    @type("number") radius: number;
}

class Player extends Schema {
    @type({ set: Effect }) effects = new SetSchema<Effect>();
}

JavaScript

const schema = require('@colyseus/schema');
const Schema = schema.Schema;
const SetSchema = schema.SetSchema;

class Effect extends Schema {
}
schema.defineTypes(Effect, {
  radius: "number",
});

class Player extends Schema {
    constructor () {
        super();

        this.effects = new SetSchema();
    }
}
schema.defineTypes(Player, {
  effects: { set: Effect }
});

`set.add()`¶

Appends an item to the SetSchema object.

const set = new SetSchema<number>();
set.add(1);
set.add(2);
set.add(3);

`set.delete()`¶

Delete an item by its value.

set.delete("three");

`set.has()`¶

Returns a boolean value wheter an item exists in the Collection or not.

if (set.has("two")) {
    console.log("Exists!");
} else {
    console.log("Does not exist!");
}

`set.size`¶

Return the number of elements in a SetSchema object.

const set = new SetSchema<number>();
set.add(10);
set.add(20);
set.add(30);

console.log(set.size);
// output: 3

More methods available for Set

Have a look at the MDN Documentation.

CollectionSchema¶

CollectionSchema is only implemented in JavaScript

The CollectionSchema can only be used with JavaScript so far. Haxe, C#, LUA and C++ clients are not supported yet.

The CollectionSchema works similarly as the ArraySchema, with the caveat that you don't have control over its indexes.

TypeScript

import { Schema, CollectionSchema, type } from "@colyseus/schema";

class Item extends Schema {
    @type("number") damage: number;
}

class Player extends Schema {
    @type({ collection: Item }) items = new CollectionSchema<Item>();
}

JavaScript

const schema = require('@colyseus/schema');
const Schema = schema.Schema;
const CollectionSchema = schema.CollectionSchema;

class Item extends Schema {
}
schema.defineTypes(Item, {
  damage: "number",
});

class Player extends Schema {
    constructor () {
        super();

        this.items = new CollectionSchema();
    }
}
schema.defineTypes(Player, {
  items: { collection: Item }
});

`collection.add()`¶

Appends an item to the CollectionSchema object.

const collection = new CollectionSchema<number>();
collection.add(1);
collection.add(2);
collection.add(3);

`collection.at()`¶

Gets an item at the specified index.

const collection = new CollectionSchema<string>();
collection.add("one");
collection.add("two");
collection.add("three");

collection.at(1);
// output: "two"

`collection.delete()`¶

Delete an item by its value.

collection.delete("three");

`collection.has()`¶

Returns a boolean value wheter an item exists in the Collection or not.

if (collection.has("two")) {
    console.log("Exists!");
} else {
    console.log("Does not exist!");
}

`collection.size`¶

Return the number of elements in a CollectionSchema object.

const collection = new CollectionSchema<number>();
collection.add(10);
collection.add(20);
collection.add(30);

console.log(collection.size);
// output: 3

`collection.forEach()`¶

The forEach() method executes a provided function once per each index/value pair in the CollectionSchema object, in insertion order.

collection.forEach((value, at) => {
    console.log("at =>", at)
    console.log("value =>", value)
});

Filtering data per client¶

This feature is experimental

The @filter()/@filterChildren() are experimental and may not be optimized for fast-paced games.

Filtering is meant to hide portions of your state for a particular client, to avoid cheating in case a player decides to inspect data coming from the network and seeing the unfiltered state information.

The data filters are callbacks that are going to be triggered per client and per field (or per child structure, in case of @filterChildren). If the filter callback returns true the field data is going to be sent for that particular client, otherwise, the data is not going to be sent for that client.

Note that the filter function does not re-run automatically if its dependencies change, but only if the filtered field (or its children) are updated. See this issue for a workaround.

`@filter()` property decorator¶

The @filter() property decorator can be used to filter out entire Schema fields.

Here's how the @filter() signature looks like:

TypeScript

class State extends Schema {
    @filter(function(client, value, root) {
        // client is:
        //
        // the current client that's going to receive this data. you may use its
        // client.sessionId, or other information to decide whether this value is
        // going to be synched or not.

        // value is:
        // the value of the field @filter() is being applied to

        // root is:
        // the root instance of your room state. you may use it to access other
        // structures in the process of decision whether this value is going to be
        // synched or not.
    })
    @type("string") field: string;
}

JavaScript

const schema = require('@colyseus/schema');
class State extends schema.Schema {}

schema.defineTypes(State, {
    field: "string"
});

schema.filter(function(client, value, root) {
    // client is:
    //
    // the current client that's going to receive this data. you may use its
    // client.sessionId, or other information to decide whether this value is
    // going to be synched or not.

    // value is:
    // the value of the field @filter() is being applied to

    // root is:
    // the root instance of your room state. you may use it to access other
    // structures in the process of decision whether this value is going to be
    // synched or not.
    return true;
})(State.prototype, "field");

`@filterChildren()` property decorator¶

The @filterChildren() property decorator can be used to filter out items inside arrays, maps, sets, etc. Its signature is pretty much the same as @filter(), with the addition of the key parameter before the value - representing each item inside a ArraySchema, MapSchema, CollectionSchema, etc.

TypeScript

class State extends Schema {
    @filterChildren(function(client, key, value, root) {
        // client is:
        //
        // the current client that's going to receive this data. you may use its
        // client.sessionId, or other information to decide whether this value is
        // going to be synched or not.

        // key is:
        // the key of the current value inside the structure

        // value is:
        // the current value inside the structure

        // root is:
        // the root instance of your room state. you may use it to access other
        // structures in the process of decision whether this value is going to be
        // synched or not.
    })
    @type([Cards]) cards = new ArraySchema<Card>();
}

JavaScript

const schema = require('@colyseus/schema');
class State extends schema.Schema {}

schema.defineTypes(State, {
    cards: [Card]
});

schema.filterChildren(function(client, key, value, root) {
    // client is:
    //
    // the current client that's going to receive this data. you may use its
    // client.sessionId, or other information to decide whether this value is
    // going to be synched or not.

    // key is:
    // the key of the current value inside the structure

    // value is:
    // the current value inside the structure

    // root is:
    // the root instance of your room state. you may use it to access other
    // structures in the process of decision whether this value is going to be
    // synched or not.
    return true;
})(State.prototype, "cards");

Example: In a card game, the relevant data of each card should be available only for the owner of the card, or on certain conditions (e.g. card has been discarded)

See @filter() callback signature:

TypeScript

import { Client } from "colyseus";

class Card extends Schema {
    @type("string") owner: string; // contains the sessionId of Card owner
    @type("boolean") discarded: boolean = false;

    /**
     * DO NOT USE ARROW FUNCTION INSIDE `@filter`
     * (IT WILL FORCE A DIFFERENT `this` SCOPE)
     */
    @filter(function(
        this: Card, // the instance of the class `@filter` has been defined (instance of `Card`)
        client: Client, // the Room's `client` instance which this data is going to be filtered to
        value: Card['number'], // the value of the field to be filtered. (value of `number` field)
        root: Schema // the root state Schema instance
    ) {
        return this.discarded || this.owner === client.sessionId;
    })
    @type("uint8") number: number;
}

JavaScript

const schema = require('@colyseus/schema');

class Card extends schema.Schema {}
schema.defineTypes(Card, {
    owner: "string",
    discarded: "boolean",
    number: "uint8"
});

/**
 * DO NOT USE ARROW FUNCTION INSIDE `@filter`
 * (IT WILL FORCE A DIFFERENT `this` SCOPE)
 */
schema.filter(function(client, value, root) {
    return this.discarded || this.owner === client.sessionId;
})(Card.prototype, "number");

Client-side¶

C#, C++, Haxe

When using statically typed languages, you need to generate the client-side schema files based on your TypeScript schema definitions. See generating schema on the client-side.

Callbacks¶

When applying state changes coming from the server, the client-side is going to trigger callbacks on local instances according to the change being applied.

The callbacks are triggered based on instance reference. Make sure to attach the callback on the instances that are actually changing on the server.

onAdd (instance, key)
onRemove (instance, key)
onChange (changes) (on Schema instance)
onChange (instance, key) (on collections: MapSchema, ArraySchema, etc.)
listen()

`onAdd (instance, key)`¶

The onAdd callback can only be used in collection of items (MapSchema, ArraySchema, etc.). The onAdd callback is called with the new instance and its key on holder object as argument.

JavaScript

room.state.players.onAdd = (player, key) => {
    console.log(player, "has been added at", key);

    // add your player entity to the game world!

    // If you want to track changes on a child object inside a map, this is a common pattern:
    player.onChange = function(changes) {
        changes.forEach(change => {
            console.log(change.field);
            console.log(change.value);
            console.log(change.previousValue);
        })
    };

    // force "onChange" to be called immediatelly
    player.triggerAll();
};

LUA

room.state.players['on_add'] = function (player, key)
    print("player has been added at", key);

    -- add your player entity to the game world!

    -- If you want to track changes on a child object inside a map, this is a common pattern:
    player['on_change'] = function(changes)
        for i, change in ipairs(changes) do
            print(change.field)
            print(change.value)
            print(change.previousValue)
        end
    end

    -- force "on_change" to be called immediatelly
    player.trigger_all()
end

C#

room.State.players.OnAdd += (Player player, string key) =>
{
    Debug.Log("player has been added at " + key);

    // add your player entity to the game world!

    // If you want to track changes on a child object inside a map, this is a common pattern:
    player.OnChange += (changes) =>
    {
        changes.ForEach((obj) =>
        {
            Debug.Log(obj.Field);
            Debug.Log(obj.Value);
            Debug.Log(obj.PreviousValue);
        });
    };

    // force "OnChange" to be called immediatelly
    e.Value.TriggerAll();
};

`onRemove (instance, key)`¶

The onRemove callback can only be used in maps (MapSchema) and arrays (ArraySchema). The onRemove callback is called with the removed instance and its key on holder object as argument.

JavaScript

room.state.players.onRemove = (player, key) => {
    console.log(player, "has been removed at", key);

    // remove your player entity from the game world!
};

LUA

room.state.players['on_remove'] = function (player, key)
    print("player has been removed at " .. key);

    -- remove your player entity from the game world!
end

C#

room.State.players.OnRemove += (Player player, string key) =>
{
    Debug.Log("player has been removed at " + key);

    // remove your player entity from the game world!
};

`onChange (changes: DataChange[])`¶

onChange works differently for direct Schema references and collection structures. For onChange on collection structures (array, map, etc.), check here.

You can register the onChange to track a Schema instance's property changes. The onChange callback is triggered with an array of changed properties, along with its previous values.

JavaScript

room.state.onChange = (changes) => {
    changes.forEach(change => {
        console.log(change.field);
        console.log(change.value);
        console.log(change.previousValue);
    });
};

LUA

room.state['on_change'] = function (changes)
    for i, change in ipairs(changes) do
        print(change.field)
        print(change.value)
        print(change.previousValue)
    end
end

C#

room.State.OnChange += (changes) =>
{
    changes.ForEach((obj) =>
    {
        Debug.Log(obj.Field);
        Debug.Log(obj.Value);
        Debug.Log(obj.PreviousValue);
    });
};

You cannot register the onChange callback on objects that haven't been synchronized with the client-side yet.

`onChange (instance, key)`¶

onChange works differently for direct Schema references and collection structures. For onChange on Schema structures, check here.

This callback is triggered whenever a collection of primitive types (string, number, boolean, etc.) updates some of its values.

JavaScript

room.state.players.onChange = (player, key) => {
    console.log(player, "have changes at", key);
};

LUA

room.state.players['on_change'] = function (player, key)
    print("player have changes at " .. key);
end

C#

room.State.players.OnChange += (Player player, string key) =>
{
    Debug.Log("player have changes at " + key);
};

If you'd like to detect changes inside a collection of non-primitive types (holding Schema instances),use onAdd and register onChange on them.

onChange, onAdd and onRemove are exclusive

The onChange callback is not triggered during onAdd or onRemove.

Consider registering onAdd and onRemove if you need to detect changes during these steps too.

`.listen(prop, callback)`¶

Listens for a single property change.

.listen() is currently only available for JavaScript/TypeScript.

Parameters:

property: the property name you'd like to listen for changes.
callback: the callback that is going to be triggered when property changes.

state.listen("currentTurn", (currentValue, previousValue) => {
    console.log(`currentTurn is now ${currentValue}`);
    console.log(`previous value was: ${previousValue}`);
});

The .listen() method returns a function that is meant to unregister the listener:

const removeListener = state.listen("currentTurn", (currentValue, previousValue) => {
    // ...
});

// later on, if you don't need the listener anymore, you can call `removeListener()` to stop listening for `"currentTurn"` changes.
removeListener();

What's the difference between listen and onChange?

The .listen() method is a shorthand for onChange on a single property. Below is a rewrite from .listen() to onChange:

state.onChange = function(changes) {
    changes.forEach((change) => {
        if (change.field === "currentTurn") {
            console.log(`currentTurn is now ${change.value}`);
            console.log(`previous value was: ${change.previousValue}`);
        }
    })
}

Client-side schema generation¶

The schema-codegen is a tool that transpiles your server-side schema definition files to be used in the client-side:

To be able to decode the state in the client-side, its local schema definitions must be compatible with the schema definitions in the server.

Not required when using JavaScript SDK

Using schema-codegen is only required when using statically typed languages in the client-side, such as C#, Haxe, etc.

Usage:

To see the usage, From your terminal, cd into your server's directory and run the following command:

npx schema-codegen --help

Output:

schema-codegen [path/to/Schema.ts]

Usage (C#/Unity)
    schema-codegen src/Schema.ts --output client-side/ --csharp --namespace MyGame.Schema

Valid options:
    --output: fhe output directory for generated client-side schema files
    --csharp: generate for C#/Unity
    --cpp: generate for C++
    --haxe: generate for Haxe
    --ts: generate for TypeScript
    --js: generate for JavaScript
    --java: generate for Java

Optional:
    --namespace: generate namespace on output code

Example: Unity / C¶

Below is a real example to generate the C# schema files from the demo Unity project.

npx schema-codegen src/rooms/schema/* --csharp --output ../Assets/Scripts/States/"
generated: Player.cs
generated: State.cs

Using npm scripts:

For short, it is recommended to have your schema-codegen arguments configured under a npm script in your package.json:

"scripts": {
    "schema-codegen": "schema-codegen src/rooms/schema/* --csharp --output ../Assets/Scripts/States/"
}

This way you can run npm run schema-codegen rather than the full command:

npm run schema-codegen
generated: Player.cs
generated: State.cs

Versioning and backwards/forwards compability¶

Backwards/fowards compatibility is possible by declaring new fields at the end of existing structures, and earlier declarations to not be removed, but be marked @deprecated() when needed. See a versioning example below.

Live version 1

import { Schema, type, deprecated } from "@colyseus/schema";

class MyState extends Schema {
    @type("string") myField: string;
}

Live version 2

import { Schema, type, deprecated } from "@colyseus/schema";

class MyState extends Schema {
    // Flag field as deprecated.
    @deprecated() @type("string") myField: string;

    // To allow your server to play nicely with multiple client-side versions.
    @type("string") newField: string;
}

Live version 3

import { Schema, type, deprecated } from "@colyseus/schema";

class MyState extends Schema {
    // Flag field as deprecated.
    @deprecated() @type("string") myField: string;

    // Flag field as deprecated again.
    @deprecated() @type("string") newField: string;

    // New fields always at the end of the structure
    @type("string") anotherNewField: string;
}

This is particularly useful for native-compiled targets, such as C#, C++, Haxe, etc - where the client-side can potentially not have the most up-to-date version of the schema definitions.

Limitations and best practices¶

Each Schema structure can hold up to 64 fields. If you need more fields, use nested Schema structures.
NaN or null numbers are encoded as 0
null strings are encoded as ""
Infinity numbers are encoded as Number.MAX_SAFE_INTEGER
Multi-dimensional arrays are not supported. See how to use 1D arrays as multi-dimensional
@colyseus/schema encoding order is based on field definition order.
- Both encoder (server) and decoder (client) must have same schema definition.
- The order of the fields must be the same.

Collections¶

Collection types (ArraySchema, MapSchema, etc) must hold items of the same type, or share the same base type.

The following example is supported:

class Item extends Schema {/* base Item fields */}
class Weapon extends Item {/* specialized Weapon fields */}
class Shield extends Item {/* specialized Shield fields */}

class Inventory extends Schema {
    @type({ map: Item }) items = new MapSchema<Item>();
}

const inventory = new Inventory();
inventory.set("left", new Weapon());
inventory.set("right", new Shield());

State Synchronization » Schema¶

How to define synchronizable structures¶

Defining a Schema structure¶

Using the state within your Room¶

Working with schemas¶

Primitive types¶

Complex types¶

Collections of items¶

ArraySchema¶

array.push()¶

array.pop()¶

array.shift()¶

array.unshift()¶

array.indexOf()¶

array.splice()¶

array.forEach()¶

MapSchema¶

map.get()¶

map.set()¶

map.delete()¶

map.size¶

map.forEach()¶

SetSchema¶

set.add()¶

set.delete()¶

set.has()¶

set.size¶

CollectionSchema¶

collection.add()¶

collection.at()¶

collection.delete()¶

collection.has()¶

collection.size¶

collection.forEach()¶

Filtering data per client¶

@filter() property decorator¶

@filterChildren() property decorator¶

Client-side¶

Callbacks¶

onAdd (instance, key)¶

onRemove (instance, key)¶

onChange (changes: DataChange[])¶

onChange (instance, key)¶

.listen(prop, callback)¶

Client-side schema generation¶

Example: Unity / C¶

Versioning and backwards/forwards compability¶

Limitations and best practices¶

Collections¶

Defining a `Schema` structure¶

Using the state within your `Room`¶

`array.push()`¶

`array.pop()`¶

`array.shift()`¶

`array.unshift()`¶

`array.indexOf()`¶

`array.splice()`¶

`array.forEach()`¶

`map.get()`¶

`map.set()`¶

`map.delete()`¶

`map.size`¶

`map.forEach()`¶

`set.add()`¶

`set.delete()`¶

`set.has()`¶

`set.size`¶

`collection.add()`¶

`collection.at()`¶

`collection.delete()`¶

`collection.has()`¶

`collection.size`¶

`collection.forEach()`¶

`@filter()` property decorator¶

`@filterChildren()` property decorator¶

`onAdd (instance, key)`¶

`onRemove (instance, key)`¶

`onChange (changes: DataChange[])`¶

`onChange (instance, key)`¶

`.listen(prop, callback)`¶