--- name: dev-multiplayer-colyseus-state description: Colyseus state schema definition, types, decorators, and serialization patterns. Use when defining room state. category: multiplayer --- # Colyseus State Schema Define efficient binary-serializable state for Colyseus rooms using @colyseus/schema. ## When to Use Use when: - Defining room state schemas - Creating player/entity state - Setting up state collections - Optimizing network bandwidth ## Schema Types ```typescript import { Schema, type, MapSchema, ArraySchema } from '@colyseus/schema'; // Primitive types @type('string') // String @type('number') // Number (float) @type('uint8') // Unsigned 8-bit (0-255) @type('uint16') // Unsigned 16-bit (0-65535) @type('uint32') // Unsigned 32-bit @type('int8') // Signed 8-bit @type('int16') // Signed 16-bit @type('int32') // Signed 32-bit @type('boolean') // Boolean @type('float32') // 32-bit float // Collection types @type({ map: PlayerState }) // Map @type([PlayerState]) // Array ``` ## Basic Player State ```typescript import { Schema, type } from '@colyseus/schema'; class PlayerState extends Schema { @type('string') clientId: string = ''; @type('uint8') team: number = 0; // 0 = orange, 1 = blue @type('float32') x: number = 0; @type('float32') y: number = 0; @type('float32') z: number = 0; @type('float32') rotation: number = 0; @type('uint16') score: number = 0; @type('boolean') isAlive: boolean = true; } ``` ## Room State Schema ```typescript import { Schema, type, MapSchema } from '@colyseus/schema'; class GameRoomState extends Schema { @type({ map: PlayerState }) players = new MapSchema(); @type('uint8') phase: number = 0; // 0=waiting, 1=playing, 2=ended @type('uint16') orangeScore: number = 0; @type('uint16') blueScore: number = 0; } ``` ## Complex Nested Schema ```typescript class Vector3Schema extends Schema { @type('float32') x: number = 0; @type('float32') y: number = 0; @type('float32') z: number = 0; } class PlayerState extends Schema { @type('string') clientId: string = ''; @type(Vector3Schema) position: Vector3Schema = new Vector3Schema(); @type(Vector3Schema) velocity: Vector3Schema = new Vector3Schema(); @type('uint16') score: number = 0; @type('uint8') health: number = 100; @type('uint8') inkTank: number = 100; @type('boolean') isAlive: boolean = true; } class TeamScore extends Schema { @type('uint16') paintCoverage: number = 0; @type('uint16') kills: number = 0; @type('uint16') deaths: number = 0; @type('boolean') hasWon: boolean = false; } class MatchState extends Schema { @type('string') phase: string = 'waiting'; @type('uint16') timeRemaining: number = 180; @type({ map: TeamScore }) teamScores = new MapSchema(); @type({ map: PlayerState }) players = new MapSchema(); @type([PaintSplat]) paintSplats = new ArraySchema(); } ``` ## Using State in Room Handler ```typescript export class GameRoom extends Room { onCreate(options: any) { this.setState(new GameRoomState()); } onJoin(client: Client, options: any) { const player = new PlayerState(); player.clientId = client.sessionId; player.x = 0; player.y = 0; player.z = 0; // Assign team const orangeCount = this.getOrangeCount(); const blueCount = this.getBlueCount(); player.team = orangeCount <= blueCount ? 0 : 1; this.state.players.set(client.sessionId, player); } onLeave(client: Client, consented: boolean) { this.state.players.delete(client.sessionId); } onMessage(client: Client, data: any) { const player = this.state.players.get(client.sessionId); if (!player) return; // Update player state if (data.type === 'move') { player.x = data.x; player.y = data.y; player.z = data.z; } } private getOrangeCount(): number { return Array.from(this.state.players.values()) .filter(p => p.team === 0).length; } private getBlueCount(): number { return Array.from(this.state.players.values()) .filter(p => p.team === 1).length; } } ``` ## Array Schema Operations ```typescript class MyState extends Schema { @type([PlayerState]) players = new ArraySchema(); } // Add to array this.state.players.push(new PlayerState()); // Remove from array this.state.players.splice(index, 1); // Iterate this.state.players.forEach((player, index) => { console.log(player.clientId); }); ``` ## Type Selection Guidelines | Use Case | Type | Bytes | Range | |----------|------|-------|-------| | Player health 0-100 | uint8 | 1 | 0-255 | | Score 0-65535 | uint16 | 2 | 0-65535 | | Coordinates (-100 to 100) | float32 | 4 | ±3.4E38 | | Team enum | uint8 | 1 | 0-255 | | Player ID | string | variable | text | | Boolean flag | boolean | 1 | true/false | ## Best Practices 1. **Use smallest type that fits** - Saves bandwidth 2. **Always add @type decorators** - Required for serialization 3. **Use collections efficiently** - MapSchema for dynamic keys, ArraySchema for ordered lists 4. **Initialize default values** - Prevents undefined issues 5. **Keep state flat** - Deep nesting increases complexity ## Common Mistakes | ❌ Wrong | ✅ Right | |----------|----------| | Missing @type decorator | Always add `@type('string')` | | Using `number` for small ranges | Use `uint8`, `uint16` for savings | | Deep nesting (4+ levels) | Keep state shallow | | Not initializing defaults | Set default: `x: number = 0` | ## Reference - [Schema Documentation](https://docs.colyseus.io/state-synchronization/) - [Schema API](https://docs.colyseus.io/state-synchronization/schema-api/) --- ## Schema Definition Best Practices (Updated 2026-01-28) From arch-003 retrospective - proven patterns for @colyseus/schema. ### Complete Player Schema Pattern ```typescript import { Schema, type } from '@colyseus/schema'; /** * Player state schema for server-authoritative multiplayer * * Type Selection Guidelines: * - uint8: 0-255 (health, armor, small counters) * - uint16: 0-65535 (scores, larger counters) * - float32: Coordinates, rotation (precision needed) * - string: Variable text (sessionId, weapon names) * - boolean: Flags (isAlive, connected) */ export class PlayerState extends Schema { // Position (float32 for precision) @type('float32') x: number = 0; @type('float32') y: number = 0; @type('float32') z: number = 0; // Rotation (degrees or radians) @type('float32') rotation: number = 0; // Combat stats (uint8 sufficient for 0-100 ranges) @type('uint8') health: number = 100; @type('uint8') armor: number = 0; // Weapon (string for flexibility - consider enum for type safety) @type('string') weapon: string = 'blaster'; // Score tracking @type('uint8') kills: number = 0; @type('boolean') isAlive: boolean = true; } ``` ### Complete Room State Pattern ```typescript import { Schema, type, MapSchema } from '@colyseus/schema'; import { PlayerState } from './PlayerState'; export class ArenaState extends Schema { // Players map - keyed by sessionId @type({ map: PlayerState }) players = new MapSchema(); // Room settings @type('string') mapSeed: string = ''; // Match state @type('uint16') playersAlive: number = 0; @type('string') phase: string = 'lobby'; // lobby, playing, ended } ``` ### Schema Type Selection Guide | Data | Type | Bytes | Range | Example | |------|------|-------|-------|---------| | Health 0-100 | uint8 | 1 | 0-255 | `@type('uint8') health: number = 100` | | Armor 0-100 | uint8 | 1 | 0-255 | `@type('uint8') armor: number = 0` | | Kills 0-63 | uint8 | 1 | 0-255 | `@type('uint8') kills: number = 0` | | Score 0-65535 | uint16 | 2 | 0-65535 | `@type('uint16') score: number = 0` | | Position X/Y/Z | float32 | 4 | ±3.4E38 | `@type('float32') x: number = 0` | | Rotation | float32 | 4 | ±3.4E38 | `@type('float32') rotation: number = 0` | | Session ID | string | variable | text | `@type('string') sessionId: string = ''` | | Weapon name | string | variable | text | `@type('string') weapon: string = ''` | | Alive status | boolean | 1 | true/false | `@type('boolean') isAlive: boolean = true` | | Player map | MapSchema | 4+ bytes | dynamic | `@type({ map: PlayerState })` | ### Common Schema Mistakes | ❌ Wrong | ✅ Right | Why | |----------|----------|-----| | `@type()` missing | `@type('uint8')` | Required for serialization | | `@type('number')` for health | `@type('uint8')` | Saves 3 bytes per player | | `health` without default | `health: number = 100` | Prevents undefined | | Using `Array` for players | `MapSchema` | Efficient lookup by ID | **Sources:** - https://docs.colyseus.io/colyseus/server/schema/ - **Learned from arch-003 retrospective (2026-01-28)** --- Source attribution: feliperyba Original project: https://github.com/feliperyba/ralph-orchestra/blob/7a74951367fe9bec093753f6eaa4d0eeda9428e5/.claude/skills/dev-multiplayer-colyseus-state/SKILL.md License: MIT License information: https://opensource.org/license/mit Original upstream instructions; 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