为什么我的 SetInterval 开始无限循环

如何解决为什么我的 SetInterval 开始无限循环

因此，此代码用于制作蛇游戏，我正在使用 setInterval 使用画布制作一些动画。现在，当我尝试这样做时，它会出现无限循环的错误。我不知道为什么或如何解决这个问题。
代码如下：

    let
      canvas = document.getElementById("canvas"),ctx = canvas.getContext("2d"),width = canvas.width,height = canvas.height,blockSize = 10,widthInBlocks = width / blockSize,heightInBlocks = height / blockSize,score = 0;

    // Code for the border -- or would we use `.strokeRect`?
    ctx.fillStyle = "Gray"
    ctx.fillRect(0,blockSize,height);
    ctx.fillRect(0,width,blockSize);
    ctx.fillRect(0,height - blockSize,blockSize);
    ctx.fillRect(width - blockSize,height);

    // Code for tracking score
    ctx.font = "20px Courier";
    ctx.fillStyle = "Black"
    ctx.textAlign = "left"
    ctx.textBaseline = "top"
    ctx.fillText("score: " + score,blockSize)

    var gameOver = function() {
      clearInterval();
      ctx.font = "60px Courier";
      ctx.fillStyle = "Black"
      ctx.textAlign = "center";
      ctx.textBaseline = "middle";
      ctx.fillText("Game Over",width / 2,height / 2);
    }



    var gameOver = function() {
      clearInterval(intervalId);
      ctx.font = "60px Courier";
      ctx.textAlign = "center";
      ctx.textBaseline = "middle"
      ctx.fillText("Game over",height / 2);
    }

    var circle = function(x,y,radius,fillCircle) {
      ctx.beginPath();
      ctx.arc(x,Math.PI * 2,false)
      if (fillCircle) {
        ctx.fill();
      } else {
        ctx.stroke();
      }
    }

    var Block = function(col,row) {
      this.col = col;
      this.row = row;
    }

    Block.prototype.drawSquare = function(color) {
      var x = this.col * blockSize;
      var y = this.row * blockSize;
      ctx.fillStyle = color;
      ctx.fillRect(x,blockSize);
    }

    Block.prototype.drawCircle = function(color) {
      var centerX = this.col * blockSize + blockSize / 2;
      var centerY = this.row * blockSize + blockSize / 2;
      ctx.fillStyle = color;
      circle(centerX,centerY,blockSize / 2,true);
    }

    var Snake = function() {
      this.segments = [
        new Block(7,5),new Block(6,new Block(5,5)
      ];
      this.direction = "right"
      this.nextDirection = "right"
    }

    Snake.prototype.draw = function() {
      for (var i = 0; i < this.segments.length; i++)
        this.segments[i].drawSquare("Blue")
    }


    Snake.prototype.move = function() {
      var head = this.segments[0];
      var newHead;

      this.direction = this.nextDirection

      if (this.direction === "right") {
        newHead = new Block(head.col + 1,head.row);
      } else if (this.direction === "down") {
        newHead = new Block(head.col,head.row + 1);
      } else if (this.direction === "left") {
        newHead = new Block(head.col - 1,head.row)
      } else if (this.direction === "up") {
        newHead = new Block(head.col,head.row - 1)
      }

      if (this,checkCollision(newHead)) {
        gameOver();
        return;
      }

      this.segments.unshift(newHead);

      if (newHead.equal(apple.position)) {
        score++;
        apple.move();
      } else {
        this.segments.pop()
      }
    }

    Snake.prototype.checkCollision = function(head) {
      var leftCollision = (head.col === 0);
      var topCollision = (head.row === 0);
      var rightCollision = (head.col === widthInBlocks - 1);
      var bottomCollision = (head.row === heightInBlocks - 1);


      var wallCollision = leftCollision || topCollision ||
        rightCollision || bottomCollision;

      var selfCollision = false

      for (var i = 0; i < this.segments.legnth; i++) {
        if (head.equal(this.segments.length[i])) {
          selfCollision = true;
        }
      }

      return wallCollision || selfCollision;
    }
    Snake.prototype.setDirection = function(newDirection) {
      if (this.direction === "right" && newDirection === "left") {
        return;
      } else if (this.direction === "down" && newDirection === "up") {
        return;
      } else if (this.direction === "left" && newDirection === "right") {
        return;
      }
    
    this.nextDirection = newDirection;
}
var Apple = function () {
this.position = new Block(10,10);
}

Apple.prototype.draw = function () {
this.position.drawCircle("Red");
}

Apple.prototype.move = function () {
var randomCol = Math.floor(Math.random() * (widthInBlocks - 2)) + 1
var randomrow = Math.floor(Math.random() * (heightInBlocks - 2)) + 1
this.position = new Block(randomCol,randomrow);
}
    var snake = new Snake();
    snake.draw()
    var apple = new Apple();
    apple.draw()
   
var intervalId = setInterval(function () {
ctx.clearRect(0,height);
drawscore();
snake.move();
snake.draw();
apple.draw();
drawBorder();
},100)

var directions = {
37: "left",38: "up",39: "right",40: "down"
}

$("body").keydown(function (event) {
var newDirection = directions[event.keyCode];
if (newDirection !== undefined) {
snake.setDirection(newDirection);
}
})

有什么问题吗？ 第 170 行出错。 我不知道该怎么做，也不知道错误意味着什么。请有人帮助我