---
title: "Snake and maze-snake rules: API"
package: "@phaser-ae/snake"
tier: Free
version: 3.0.0-3
released: 2026-10-14
updated: 2026-10-20
description: "Grid snake games as configurable sessions, with buffered turns, food on free cells, speed curves, wall policies, authored maze waves, a clock, lives and scoring."
url: https://phaser.io/packs/snake/api
site: Phaser - https://phaser.io
---

# Snake and maze-snake rules: API

`@phaser-ae/snake` — Grid snake games as configurable sessions: buffered turns, free-cell food, capped speed curves, wall policies, maze waves, timers and lives, as in Nibbler.

## The pack

### `snake`

```ts
function snake(): Pack<{ snake: typeof api }>
```

Install the renderer-independent Snake/Nibbler rules API as `game.snake`.

## Helpers

### `createSnake`

```ts
function createSnake(config: SnakeConfig)
```

Create an independent Snake board; a {@link SnakeGame } or the host chooses step timing.

### `createSnakeGame`

```ts
function createSnakeGame(config: SnakeGameConfig)
```

Create a Snake/Nibbler session.

### `DEFAULT_SNAKE_LEGEND`

```ts
const DEFAULT_SNAKE_LEGEND: SnakeMazeLegend
```

`#` wall, `.` food, space empty, `> < ^ v` the head and its heading.

### `NIBBLER_WAVES`

```ts
const NIBBLER_WAVES: readonly SnakeWave[]
```

Six authored 31×21 Nibbler-style waves. Rock-Ola's 32 original maze layouts are not published as
data, so these are credible approximations built on the documented structure: one-cell corridors,
no dead ends (a halted snake can always be steered on), waves 3 and 6 are open fields bounded only
by the outer wall, and the cycle repeats faster (wave 7 is wave 1 at a higher speed).

### `parseSnakeMaze`

```ts
function parseSnakeMaze( maze: readonly string[], legend: SnakeMazeLegend = DEFAULT_SNAKE_LEGEND, ): Partial<SnakeConfig> & { cols: number; rows: number }
```

Parse an ASCII maze into board fields: `cols`, `rows`, `obstacles`, `foods` and, when a head
marker (`> < ^ v`) is present, `start` and `direction`. The body trails straight behind the
head for `startLength` cells, shortened at a wall. Unknown characters are an error.

### `snakeGamePreset`

```ts
function snakeGamePreset( kind: SnakeGameKind = "classic", options: SnakeGameOptions = {}, ): SnakeGameConfig
```

A complete session preset. `classic`: walled board, one food at a time, speed rising per food to
a cap, one life, play until you crash or fill the board. `wrap`: the same with wrapping edges and
three foods. `nibbler`: Rock-Ola 1982 rules (see the pack docs). Every field can be overridden;
`board` overrides merge into the preset board.

### `snakeObstacles`

```ts
function snakeObstacles(layout: SnakeObstacleLayout, cols: number, rows: number): Cell[]
```

Obstacle cells for a `cols × rows` board: `box` an inner border with a gap in the middle of each
side, `pillars` 2×2 blocks on a regular lattice, `bars` two horizontal bars at the quarter heights
with a central gap. The centre row (`floor(rows/2)`, where the default start lies) is always kept
clear. Small boards simply get fewer cells.

### `snakePreset`

```ts
function snakePreset( kind: "classic" | "orchard" | "maze" = "classic", options: Partial<SnakeConfig> = {}, ): SnakeConfig
```

Public authored board presets; dimensions and every rule remain overrideable.

## Classes

### `Snake`

```ts
class Snake
```

Owns grid growth, food placement, turn buffering, wall policy and collision/win rules. The host (or a
{@link SnakeGame } session) decides when to call `step()`.

- `readonly cols: number` — Board width in cells.
- `readonly rows: number` — Board height in cells.
- `readonly config: SnakeConfig` — A copy of the configuration the board was built from.
- `constructor(cfg: SnakeConfig)`
- `get state()` — Copied serialisable state.
- `get body()` — Legacy mutable body array (head first); prefer `state.body`.
- `get food(): Cell` — First food, or {-1,-1} when none remains.
- `get foods()` — A copy of the foods on the board.
- `get dead()` — Whether the snake has died.
- `get won()` — Whether the goal has been met.
- `get score()` — Points scored on this board.
- `get eaten()` — Food eaten on this board.
- `get stalled()` — Consecutive steps halted against a wall (`stop` policy).
- `get direction()` — Current heading (the direction of the last move, or the initial heading).
- `isObstacle(p: Cell)` — True when `p` is a wall/obstacle cell.
- `next(from: Cell, d: Direction): Cell` — The cell one step from `from` in `d`, wrapped when wrap is on; may be off-board otherwise.
- `input(d: Direction): boolean` — Buffer a turn. Up to `queueSize` turns are remembered and applied one per step in the order pressed; each is checked against the LAST queued heading, so up-then-left inside one move works while any reversal into the neck is refused. Returns whether the turn was accepted.
- `step(): SnakeStep` — Advance one cell. Food, growth, wall policy, collisions and outcome are resolved here.
- `autoInput()` — Safe one-step steering helper; useful for an optional bot, not a claimed solver.
- `snapshot()` — A copy of the serialisable state, to save; the same as `state`.
- `restore(s: SnakeState)` — Replaces the state with a saved one from `snapshot()`. Throws if the body, foods, queue, counters or status are invalid, or the queue is longer than `queueSize`.
- `reset()` — Rebuilds the board from its configuration, as at construction: the starting body, foods and seed, with the score and counters at zero.

### `SnakeGame`

```ts
class SnakeGame
```

A complete Snake/Nibbler session around a {@link Snake} board. It owns every rule above the
board: the title/ready/playing/paused/dying/clear/over phases, lives and extra lives, wave
progression and looping, the wave timer and its stall acceleration, the speed curve and cap,
score multipliers, time bonus and the high score. The host only calls `update(dt)`, forwards
turns with `input()`, `start()` and `pause()`, and draws `state`.

- `readonly config: SnakeGameConfig` — The session configuration: a copy of what the constructor was given.
- `constructor(config: SnakeGameConfig)`
- `indexFor(n: number)` — Index of the authored wave played as wave `n`.
- `waveFor(n: number): SnakeWave | undefined` — The authored wave played as wave `n`, if any.
- `boardFor(n: number, game = this.s?.games ?? 0): SnakeConfig` — The full board config for wave `n`: base board, then the wave's maze, then its overrides.
- `limitFor(n: number)` — Time limit in seconds for wave `n` (Infinity without a timer).
- `speedFor(n: number, eaten: number)` — Cells per second for the current wave and eaten count, capped.
- `get board(): Snake` — The live board (rules for movement, food and collisions).
- `get state(): SnakeGameState` — Copied session state, including the board snapshot.
- `get phase()` — The session's lifecycle phase.
- `start(): boolean` — Begin a new game from title, game over or a won game; ignored mid-game.
- `newGame()` — Begin a new game unconditionally (keeps the high score).
- `title()` — Return to the title phase showing the first wave (keeps the high score).
- `pause(on?: boolean): boolean` — Pause or resume (toggle when `on` is omitted). Only ready/playing can pause.
- `input(d: Direction): boolean` — Buffer a turn; accepted during READY too, so a pre-pressed turn applies on the first move.
- `update(dt: number): SnakeGameEvent[]` — Advance the session by `dt` seconds (clamped to 0.25 per call). Returns what happened.
- `snapshot(): SnakeGameState` — Serializable copy of the whole session.
- `restore(state: SnakeGameState)` — Restore a snapshot taken from a session with the same config.

## Types

### `SnakeConfig`

```ts
interface SnakeConfig
```

Dimensions, body/obstacles/foods, turn buffering, wrap, wall and growth/objective policies.

- `cols: number` — Board width in cells; a whole number of at least 1. Width times height may not exceed one million cells.
- `rows: number` — Board height in cells; a whole number of at least 1. Width times height may not exceed one million cells.
- `seed?: number` — Seed for food placement.
- `wrap?: boolean` — Edges join to the opposite side instead of being walls.
- `start?: Cell` — Head cell when `body` is not authored. Defaults to the board centre.
- `body?: Cell[]` — Authored body, head first, each cell adjacent to the previous one.
- `startLength?: number` — Length of the generated straight body behind `start` when `body` is absent (default 3).
- `direction?: Direction` — Initial heading (default right).
- `obstacles?: Cell[]` — Solid cells.
- `foods?: SnakeFood[]` — Authored foods. When given, no random food is placed at construction.
- `foodCount?: number` — Random foods kept on the board while `respawnFood` is on (default 1).
- `foodGrowth?: number` — Segments added per food unless the food overrides it (default 1).
- `foodScore?: number` — Points per food unless the food overrides it (default 10).
- `respawnFood?: boolean` — Replace eaten food with a random free cell (default true; ignored for `clear-food`).
- `goal?: "fill" | "clear-food" | "score"` — Win condition besides filling the board: `fill` (default), `clear-food` or `score`.
- `targetScore?: number` — Score needed for the `score` goal (default 100).
- `queueSize?: number` — Buffered turns (default 3). Rapid key presses inside one move are honoured in order.
- `wallPolicy?: SnakeWallPolicy` — Wall/obstacle/edge behaviour (default `die`).
- `autoTurn?: boolean` — With `stop`, follow single-exit corners without input (default true for `stop`).

### `SnakeDeath`

```ts
type SnakeDeath = "wall" | "obstacle" | "self"
```

Why a snake died.

### `SnakeFood`

```ts
interface SnakeFood extends Cell
```

An authored food cell with optional appearance kind, growth and score overrides.

- `kind?: string` — Appearance/category tag for the renderer; rules ignore it. Defaults to `food`.
- `growth?: number` — Segments added when eaten; defaults to `foodGrowth`.
- `score?: number` — Base points when eaten; defaults to `foodScore`. A session may multiply it.

### `SnakeGameConfig`

```ts
interface SnakeGameConfig
```

Session rules around a {@link Snake} board: waves, lives, timer, speed curve, scoring and banners.

- `board: SnakeConfig` — Base board rules for every wave (a wave's maze and `board` override it).
- `waves?: SnakeWave[]` — Authored waves. Absent: one endless board (classic Snake).
- `loopWaves?: boolean` — After the last wave, repeat from the first with the wave number (speed, timer, multiplier) still rising (default true).
- `lives?: number` — Lives at the start (default 3).
- `maxLives?: number` — Life cap (default 99).
- `extraLifeEveryWaves?: number` — Award a life after clearing every Nth wave (0 = never).
- `extraLifeScores?: number[]` — Award a life when the score first reaches each of these totals.
- `speed?: SnakeSpeed` — Movement speed curve (default 8 cells/s flat).
- `timer?: SnakeTimer | null` — Wave countdown, or null for none.
- `scoreMultiplier?: "none" | "wave"` — `wave` multiplies food and time-bonus points by the wave number (Nibbler); `none` (default) does not.
- `keepEatenFood?: boolean` — After a death, keep the food already eaten on authored (clear-food) boards (default true).
- `readyTime?: number` — Seconds of READY before moving (default 1).
- `deathTime?: number` — Seconds the death banner shows (default 1.2).
- `clearTime?: number` — Seconds the wave-clear banner shows (default 2).
- `highScore?: number` — Initial high score (default 0).
- `startWave?: number` — First wave number (default 1).
- `legend?: SnakeMazeLegend` — Maze legend; defaults to {@link DEFAULT_SNAKE_LEGEND}.

### `SnakeGameEvent`

```ts
type SnakeGameEvent = | { type: "go" } | { type: "move" } | { type: "blocked" } | { type: "ate"; food: SnakeFood; points: number } | { type: "died"; cause: SnakeLifeLoss } | { type: "cleared"; wave: number; bonus: number } | { type: "wave"; wave: number } | { type: "extra-life"; lives: number } | { type: "game-over" } | { type: "won" }
```

Something that happened during {@link SnakeGame.update}.

### `SnakeGameKind`

```ts
type SnakeGameKind = "classic" | "wrap" | "nibbler"
```

Named session presets.

### `SnakeGameOptions`

```ts
type SnakeGameOptions = Omit<Partial<SnakeGameConfig>, "board"> & { board?: Partial<SnakeConfig>; }
```

Options accepted by {@link snakeGamePreset }: any session field, with partial board overrides.

### `SnakeGamePhase`

```ts
type SnakeGamePhase = | "title" | "ready" | "playing" | "paused" | "dying" | "clear" | "over" | "won"
```

Lifecycle of a {@link SnakeGame}.

### `SnakeGameState`

```ts
interface SnakeGameState
```

Copied, serialisable session state.

- `phase: SnakeGamePhase` — The session's lifecycle phase; `title` before the first game starts.
- `phaseTime: number` — Seconds spent in the current phase.
- `resume: SnakeGamePhase` — Phase to return to when unpaused.
- `wave: number` — 1-based wave number (keeps rising when waves loop).
- `waveIndex: number` — Index into `waves` (0 without waves).
- `lives: number` — Lives left, including the one in play.
- `score: number` — Points scored this game.
- `highScore: number` — Best score so far across games in this session; starts at the configured `highScore`.
- `timeLeft: number` — Seconds left on the wave timer (Infinity without a timer).
- `timeLimit: number` — This wave's time limit in seconds (Infinity without a timer).
- `speed: number` — Current cells per second.
- `carry: number` — Fractional progress towards the next move.
- `stall: number` — Seconds the snake has been halted against a wall.
- `bonus: number` — Bonus scored by the last wave clear.
- `cause?: SnakeLifeLoss` — Cause of the last lost life.
- `eatenTotal: number` — Food eaten in this game.
- `awarded: number` — Score thresholds already rewarded.
- `games: number` — Games started by this session; varies the food seed so each new game differs.
- `board: SnakeState` — Snapshot of the current board's state.

### `SnakeLifeLoss`

```ts
type SnakeLifeLoss = SnakeDeath | "time"
```

Why a life was lost: a board death or the wave timer running out.

### `SnakeMazeLegend`

```ts
type SnakeMazeLegend = Record<string, "wall" | "empty" | Omit<SnakeFood, "x" | "y">>
```

Character legend for {@link parseSnakeMaze}: a wall, an empty cell or a food template.

### `SnakeObstacleLayout`

```ts
type SnakeObstacleLayout = "none" | "box" | "pillars" | "bars"
```

Named obstacle layouts for open boards.

### `SnakeSpeed`

```ts
interface SnakeSpeed
```

Movement rate in cells per second: `start + perWave·(wave−1) + perFood·eaten`, capped at `max`.

- `start: number` — Cells per second on wave 1 before anything is eaten.
- `perFood?: number` — Added per food eaten on the current board (classic speed-up).
- `perWave?: number` — Added per wave after the first (Nibbler speed-up).
- `max: number` — Hard cap in cells per second.

### `SnakeState`

```ts
interface SnakeState
```

Serializable body, foods, turn queue, pending growth, the food stream's kernel state and terminal outcome.

- `body: Cell[]` — Cells the snake occupies, head first.
- `foods: SnakeFood[]` — Foods currently on the board.
- `direction: Direction` — Heading of the last move, or the initial heading before the first.
- `queue: Direction[]` — Buffered turns not yet applied, oldest first; at most `queueSize` long.
- `growth: number` — Segments still to be added: the tail stays put for this many more steps.
- `score: number` — Points scored on this board.
- `eaten: number` — Foods eaten on this board.
- `status: "playing" | "won" | "lost"` — `playing` while the round runs, `won` once the goal is met, `lost` after a fatal move.
- `random: number[]` — The food stream: four words of the kernel's `createRng` state, advanced in place as food is placed.
- `ticks: number` — Steps taken, including steps spent halted against a wall.
- `stalled?: number` — Consecutive steps spent halted against a wall (`stop` policy).
- `held?: boolean` — The queue head was refused by a wall and is being held for the next opening (`stop` policy).
- `cause?: SnakeDeath` — Cause of the loss, when lost.

### `SnakeStep`

```ts
interface SnakeStep
```

Result of one {@link Snake.step}.

- `moved: boolean` — Whether the head advanced a cell this step.
- `ate: boolean` — Whether the head moved onto a food this step.
- `dead: boolean` — Whether the snake died this step.
- `won: boolean` — Whether the goal was met this step.
- `blocked?: boolean` — The snake halted against a wall (`stop` policy).
- `food?: SnakeFood` — The food eaten this step.
- `cause?: SnakeDeath` — Cause of death this step.

### `SnakeTimer`

```ts
interface SnakeTimer
```

Per-wave countdown. Running out costs a life. `limit = max(min, seconds + perWave·(wave−1))`
unless the wave authors its own `time`. Seconds left when a wave is cleared score
`bonusPerSecond × multiplier` each. While the snake is halted against a wall for more than
`stallGrace` seconds the clock speeds up, doubling every `stallDoubling` seconds (0 disables).

- `seconds: number` — Time limit of wave 1, in seconds; at least 0.1.
- `perWave?: number` — Seconds added to the limit for each wave after the first; negative values shorten it. Default 0.
- `min?: number` — Lowest limit the per-wave change may reach, in seconds. Default 0.1.
- `bonusPerSecond?: number` — Points per whole second left when a wave is cleared, before the wave multiplier. Default 0.
- `stallGrace?: number` — Seconds halted against a wall before the clock starts running faster. Default 0.
- `stallDoubling?: number` — Seconds of further stalling over which the clock's rate doubles, up to 64 times normal; 0 (default) disables the acceleration.

### `SnakeWallPolicy`

```ts
type SnakeWallPolicy = "die" | "stop"
```

What happens when the head meets a wall, obstacle or (without wrap) the board edge.
- `die`: classic Snake. The move is fatal.
- `stop`: Nibbler. The snake halts in place (time keeps running) and, with `autoTurn`, follows a
  corridor round a corner that has exactly one way on. Biting its own body is always fatal.

### `SnakeWave`

```ts
interface SnakeWave
```

One authored wave: an ASCII maze and/or board overrides, plus optional time/speed overrides.

- `name?: string` — Display name.
- `maze?: string[]` — ASCII maze, parsed with {@link parseSnakeMaze} and the session's `legend`.
- `board?: Partial<SnakeConfig>` — Board overrides applied after the maze.
- `time?: number` — Time limit in seconds for this wave.
- `speed?: number` — Starting speed for this wave (replaces `speed.start`; per-wave/food increments still apply).

---

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