```html
Snake
Snake
Score: 0
High: 0
Arrow keys or WASD to move · Space to start/pause · R to restart
```
```typescript
type Cell = { x: number; y: number };
type Direction = { x: number; y: number };
const GRID = 20;
const CELL = 20;
const INITIAL_TICK_MS = 150;
const MIN_TICK_MS = 60;
const SPEEDUP_EVERY = 5;
const SPEEDUP_DELTA = 10;
class Game {
private canvas: HTMLCanvasElement;
private ctx: CanvasRenderingContext2D;
private scoreEl: HTMLElement;
private highEl: HTMLElement;
private snake: Cell[];
private dir: Direction;
private pendingDir: Direction | null;
private food: Cell;
private score: number;
private high: number;
private tickMs: number;
private alive: boolean;
private started: boolean;
private paused: boolean;
private tickId: number | null;
constructor(canvas: HTMLCanvasElement, scoreEl: HTMLElement, highEl: HTMLElement) {
this.canvas = canvas;
this.ctx = canvas.getContext('2d')!;
this.scoreEl = scoreEl;
this.highEl = highEl;
this.snake = [{ x: 10, y: 10 }, { x: 9, y: 10 }, { x: 8, y: 10 }];
this.dir = { x: 1, y: 0 };
this.pendingDir = null;
this.spawnFood();
this.score = 0;
const stored = localStorage.getItem('snake.high');
this.high = stored !== null ? Number(stored) : 0;
this.tickMs = INITIAL_TICK_MS;
this.alive = true;
this.started = false;
this.paused = true;
this.tickId = null;
this.updateScoreDisplay();
this.updateHighDisplay();
this.draw();
}
start(): void {
if (!this.started) {
this.started = true;
this.paused = false;
this.tick();
} else if (this.paused) {
this.paused = false;
this.tick();
}
}
togglePause(): void {
if (!this.started) return;
this.paused = !this.paused;
if (!this.paused) {
this.tick();
} else {
this.clearTick();
}
}
restart(): void {
this.clearTick();
this.snake = [{ x: 10, y: 10 }, { x: 9, y: 10 }, { x: 8, y: 10 }];
this.dir = { x: 1, y: 0 };
this.pendingDir = null;
this.spawnFood();
this.score = 0;
this.tickMs = INITIAL_TICK_MS;
this.alive = true;
this.started = false;
this.paused = true;
this.updateScoreDisplay();
this.updateHighDisplay();
this.draw();
}
private setDirection(newDir: Direction): void {
if (this.dir.x === -newDir.x && this.dir.y === -newDir.y) return;
this.pendingDir = newDir;
}
private tick(): void {
if (this.alive && !this.paused) {
this.update();
this.draw();
this.tickId = setTimeout(() => this.tick(), this.tickMs);
}
}
private clearTick(): void {
if (this.tickId !== null) {
clearTimeout(this.tickId);
this.tickId = null;
}
}
private update(): void {
if (this.pendingDir !== null) {
this.dir = this.pendingDir;
this.pendingDir = null;
}
const head = { x: this.snake[0].x + this.dir.x, y: this.snake[0].y + this.dir.y };
// Wall collision
if (head.x < 0 || head.x >= GRID || head.y < 0 || head.y >= GRID) {
this.gameOver();
return;
}
// Self collision (ignore tail that will move)
for (let i = 0; i < this.snake.length - 1; i++) {
const seg = this.snake[i];
if (seg.x === head.x && seg.y === head.y) {
this.gameOver();
return;
}
}
// Eat food
if (head.x === this.food.x && head.y === this.food.y) {
this.score++;
if (this.score % SPEEDUP_EVERY === 0) {
this.tickMs = Math.max(MIN_TICK_MS, this.tickMs - SPEEDUP_DELTA);
}
if (this.score > this.high) {
this.high = this.score;
localStorage.setItem('snake.high', this.high.toString());
this.updateHighDisplay();
}
this.spawnFood();
this.snake.unshift(head);
} else {
this.snake.unshift(head);
this.snake.pop();
}
this.updateScoreDisplay();
}
private gameOver(): void {
this.alive = false;
this.clearTick();
this.draw();
}
private spawnFood(): void {
let newFood: Cell;
do {
newFood = {
x: Math.floor(Math.random() * GRID),
y: Math.floor(Math.random() * GRID)
};
} while (this.snake.some(c => c.x === newFood.x && c.y === newFood.y));
this.food = newFood;
}
private updateScoreDisplay(): void {
this.scoreEl.textContent = `Score: ${this.score}`;
}
private updateHighDisplay(): void {
this.highEl.textContent = `High: ${this.high}`;
}
private draw(): void {
this.ctx.fillStyle = '#000';
this.ctx.fillRect(0, 0, this.canvas.width, this.canvas.height);
for (let i = 1; i < this.snake.length; i++) {
const seg = this.snake[i];
this.ctx.fillStyle = '#3aa635';
this.ctx.fillRect(seg.x * CELL, seg.y * CELL, CELL, CELL);
}
const head = this.snake[0];
this.ctx.fillStyle = '#7ed957';
this.ctx.fillRect(head.x * CELL, head.y * CELL, CELL, CELL);
this.ctx.fillStyle = '#c0392b';
this.ctx.fillRect(this.food.x * CELL, this.food.y * CELL, CELL, CELL);
if (!this.started) {
this.ctx.fillStyle = '#fff';
this.ctx.font = '20px sans-serif';
this.ctx.textAlign = 'center';
this.ctx.textBaseline = 'middle';
this.ctx.fillText('Press Space to start', this.canvas.width / 2, this.canvas.height / 2);
} else if (!this.alive) {
this.ctx.fillStyle = '#fff';
this.ctx.font = '20px sans-serif';
this.ctx.textAlign = 'center';
this.ctx.textBaseline = 'middle';
this.ctx.fillText('Game Over — press R to restart', this.canvas.width / 2, this.canvas.height / 2);
} else if (this.paused) {
this.ctx.fillStyle = '#fff';
this.ctx.font = '20px sans-serif';
this.ctx.textAlign = 'center';
this.ctx.textBaseline = 'middle';
this.ctx.fillText('Paused', this.canvas.width / 2, this.canvas.height / 2);
}
}
}
const canvas = document.getElementById('game') as HTMLCanvasElement;
const scoreEl = document.getElementById('score') as HTMLElement;
const highEl = document.getElementById('high') as HTMLElement;
const game = new Game(canvas, scoreEl, highEl);
window.addEventListener('keydown', e => {
const key = e.key;
let prevent = false;
switch (key) {
case 'ArrowUp':
case 'w':
case 'W':
game.setDirection({ x: 0, y: -1 });
prevent = true;
break;
case 'ArrowDown':
case 's':
case 'S':
game.setDirection({ x: 0, y: 1 });
prevent = true;
break;
case 'ArrowLeft':
case 'a':
case 'A':
game.setDirection({ x: -1, y: 0 });
prevent = true;
break;
case 'ArrowRight':
case 'd':
case 'D':
game.setDirection({ x: 1, y: 0 });
prevent = true;
break;
case ' ':
e.preventDefault();
if (!game.started) {
game.start();
} else {
game.togglePause();
}
return;
case 'r':
case 'R':
e.preventDefault();
game.restart();
return;
}
if (prevent) {
e.preventDefault();
}
});
```