JavaScript Canvas 实现贪吃蛇游戏：地图绘制与防反向自杀逻辑

完整 HTML5 代码示例

<!DOCTYPE html>
<html lang="en">

<head>
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <title>Document</title>
 <style>
 html,
 body {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
 }
 </style>
</head>

<body>
 <canvas width="400" height="400" style="background-color: #362E3D;">给我换chromium</canvas>

 <script>
 const map = document.getElementsByTagName('canvas')[0].getContext('2d'); // 数组存蛇身位置 一行 1-20 二行21-40 总共20*20
 var snake = [23, 22, 21]; // 数组头部蛇头 后部蛇尾
 var direction = 1; // 1右 -1左 -20上 20下
 var flag = 1; // 解决快速键盘bug
 var food = 50; // 食物位置

 function draw(x, color) {
  map.fillStyle = color;
 
 //用1-400标识没找到通用像素换算公式 最后一列分开计算
  if (x % 20 == 0) { // 最后一列
  map.fillRect(380 + 2, Math.floor(x / 21) * 20 + 2, 18, 18); // 使1-400的块标志对应像素点
  } else { // 其余列
  map.fillRect((x % 20 - 1) * 20 + 2, Math.floor(x / 20) * 20 + 2, 18, 18);
  }
  flag = 1; // draw()完后才能改变direction
 }

 let len = snake.length;
 for (let i = 0; i < len; i++)
  draw(snake[i], "#FDE5C5");

 (function () {
  let head = snake[0] + direction;

  if (head % 20 == 1 && direction == 1 || head % 20 == 0 && direction == -1 || head < 1 || head > 400 ||
  snake.includes(head))
  return alert('GG');
  snake.unshift(head);

  draw(head, "#FDE5C5");

  if (head == food) {
  while (snake.includes(food = Math.floor(Math.random() * 400 + 1)));
  // arr.includes 有的话返回true 否则false
  } else { //正常移动 没吃到才改变尾部颜色
  draw(snake.pop(), "#362E3D");
  }
  draw(food, "#EB1A4B");

  setTimeout(arguments.callee, 100); // arguments.callee 代表函数名 调用匿名函数自己
 })();

 document.onkeydown = function (event) {
  event = event || window.event; // ie中是windo.event
  if (flag) { // draw执行后(蛇移动后)才可以改变direction
  switch (event.keyCode) {
   case 37:
   direction != 1 ? direction = -1 : 0;
   break;
   case 38:
   direction != 20 ? direction = -20 : 0;
   break;
   case 39:
   direction != -1 ? direction = 1 : 0;
   break;
   case 40:
   direction != -20 ? direction = 20 : 0;
   break;
  }
  }
  flag = 0; // 等待下一次draw执行
 }
 </script>
</body>


</html>