```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 interval: 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.food = this.spawnFood();
this.score = 0;
this.high = parseInt(localStorage.getItem('snake.high') || '0', 10);
this.tickMs = INITIAL_TICK_MS;
this.alive = true;
this.started = false;
this.paused = true;
this.interval = null;
this.updateUI();
this.render();
}
start(): void {
this.started = true;
this.paused = false;
this.interval = setInterval(() => this.tick(), this.tickMs);
}
togglePause(): void {
if (!this.started) return;
this.paused = !this.paused;
if (this.paused) {
if (this.interval !== null) {
clearInterval(this.interval);
this.interval = null;
}
} else {
this.interval = setInterval(() => this.tick(), this.tickMs);
}
this.render();
}
restart(): void {
if (this.interval !== null) {
clearInterval(this.interval);
this.interval = null;
}
if (this.score > this.high) {
this.high = this.score;
localStorage.setItem('snake.high', this.high.toString());
}
this.snake = [{ x: 10, y: 10 }, { x: 9, y: 10 }, { x: 8, y: 10 }];
this.dir = { x: 1, y: 0 };
this.pendingDir = null;
this.food = this.spawnFood();
this.score = 0;
this.tickMs = INITIAL_TICK_MS;
this.alive = true;
this.started = false;
this.paused = true;
this.updateUI();
this.render();
}
private tick(): void {
if (!this.alive || this.paused) return;
if (this.pendingDir) {
this.dir = this.pendingDir;
this.pendingDir = null;
}
const head = this.snake[0];
const newHead: Cell = { x: head.x + this.dir.x, y: head.y + this.dir.y };
if (newHead.x < 0 || newHead.x >= GRID || newHead.y < 0 || newHead.y >= GRID) {
this.alive = false;
} else {
const tail = this.snake[this.snake.length - 1];
for (let i = 0; i < this.snake.length - 1; i++) {
if (this.snake[i].x === newHead.x && this.snake[i].y === newHead.y) {
this.alive = false;
break;
}
}
if (this.alive) {
this.snake.unshift(newHead);
if (newHead.x === this.food.x && newHead.y === this.food.y) {
this.score++;
this.food = this.spawnFood();
if (this.score % SPEEDUP_EVERY === 0) {
this.tickMs = Math.max(MIN_TICK_MS, this.tickMs - SPEEDUP_DELTA);
if (this.interval !== null) {
clearInterval(this.interval);
this.interval = setInterval(() => this.tick(), this.tickMs);
}
}
this.updateUI();
} else {
this.snake.pop();
}
}
}
if (!this.alive) {
if (this.interval !== null) {
clearInterval(this.interval);
this.interval = null;
}
}
this.render();
}
private spawnFood(): Cell {
let x: number, y: number;
do {
x = Math.floor(Math.random() * GRID);
y = Math.floor(Math.random() * GRID);
} while (this.snake.some(cell => cell.x === x && cell.y === y));
return { x, y };
}
private updateUI(): void {
this.scoreEl.textContent = `Score: ${this.score}`;
this.highEl.textContent = `High: ${this.high}`;
}
private render(): void {
this.ctx.fillStyle = '#000';
this.ctx.fillRect(0, 0, this.canvas.width, this.canvas.height);
this.ctx.fillStyle = '#3aa635';
for (let i = 1; i < this.snake.length; i++) {
this.ctx.fillRect(this.snake[i].x * CELL, this.snake[i].y * CELL, CELL, CELL);
}
this.ctx.fillStyle = '#7ed957';
this.ctx.fillRect(this.snake[0].x * CELL, this.snake[0].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.paused) {
this.drawText('Press Space to start');
} else if (this.started && this.paused) {
this.drawText('Paused');
} else if (!this.alive) {
this.drawText('Game Over — press R to restart');
}
}
private drawText(text: string): void {
this.ctx.fillStyle = '#fff';
this.ctx.font = '20px sans-serif';
this.ctx.textAlign = 'center';
this.ctx.textBaseline = 'middle';
this.ctx.fillText(text, this.canvas.width / 2, this.canvas.height / 2);
}
}
const canvas = document.getElementById('game') as HTMLCanvasElement;
const scoreEl = document.getElementById('score')!;
const highEl = document.getElementById('high')!;
const game = new Game(canvas, scoreEl, highEl);
window.addEventListener('keydown', (e) => {
let newDir: Direction | null = null;
switch (e.key) {
case 'ArrowUp':
case 'w':
case 'W':
newDir = { x: 0, y: -1 };
break;
case 'ArrowDown':
case 's':
case 'S':
newDir = { x: 0, y: 1 };
break;
case 'ArrowLeft':
case 'a':
case 'A':
newDir = { x: -1, y: 0 };
break;
case 'ArrowRight':
case 'd':
case 'D':
newDir = { x: 1, y: 0 };
break;
case ' ':
if (!game.started) {
game.start();
} else {
game.togglePause();
}
break;
case 'r':
case 'R':
game.restart();
break;
default:
return;
}
if (newDir && !(newDir.x === -game.dir.x && newDir.y === -game.dir.y)) {
game.pendingDir = newDir;
}
e.preventDefault();
});
```