Question

我是JS的初学者，并且我正在一个学校项目中创建自己的蛇游戏。我想分开我的功能，因此并非所有内容都在一个JS文件中。

例如，我试图将CheckForCollisions函数放到另一个JS文件中，但是如果我启动游戏时它给我一个错误，那snake.Trymove不是函数。这是我的HTML文件：

<html>
    <head>
        <title> Snake </title>
        <meta charset="utf-8"/>
        <script src="js/snake.js"></script>
        <script src="js/Collisions.js"></script>
        <script src="js/EventHandler.js"></script>
        <canvas id ="snake" width="960" height="720"></canvas>
    </head>
    <body>
    </body>
</html>

这是我要解析的主要JS文件：

window.onload = function() 
{
    const cvs = document.getElementById("snake");
    const ctx = cvs.getContext("2d");

      //here are some variables

      window.onclick = function (event) 
      {...}

      var Field = function (cols, rows, areawidth, areaheight) //pole
      {...};

       var Snake = function()
       {
       ...

         this.tryMove = function (deltaTime) 
         {
            this.movedelay += deltaTime;
            var maxmovedelay = 1 / this.speed;
            if (this.movedelay > maxmovedelay)
                return true;

            return false;
         }
        }

    this.nextMovement = function () 
        {...}

        this.move = function ()
        {...}

        this.grow = function ()
        {...}

        this.faster = function ()
        {...}

        this.slower= function ()
        {...}
    };

    var snake = new Snake();
    var field = new Field(20, 14, 48, 48);
    var score = 0;
    var health = 1;
    var gameover = true;
    var gameovertime = 1;
        var seconds = 80;

    function start ()
    {
      document.addEventListener("keydown", onKeyDown);
      drawMenu();
      newGame();
      main(0);
    }

    function tryNewGame() 
    {...}

    function newGame()
    {...}

    function continueGame() 
    {...}

    function addHamburger() 
    {...}

    function addBonushealth()
    {...}

    function addFaster()
    {...}

    function addSlower()
    {...}

    function main (thisframe)
    {
        window.requestAnimationFrame(main);
        update(thisframe);
        if (click == 0)
            drawMenu();
        else
        {
            drawField();
            drawSnake();
            drawinfoboard();

            ....
    }
        }

        var lastframe = 0;

    function update(thisframe)
    {...}

    function CheckForCollision(deltaTime)
    {
          if (snake.tryMove(deltaTime)) 
          {
            var nextmove = snake.nextMovement();
        var nx = nextmove.x;
        var ny = nextmove.y;
          }
        }

    function drawField() 
    {...}

    function drawSnake() 
    {...}

        function drawMenu()
        {...}

        function randomnumber(min, max) 
    {...}

    function onKeyDown(event)
    {...}

    start();
}

现在，如果我尝试将CheckForCollisions函数放置在单独的JS文件中，则会给我一个错误：

Uncaught TypeError: snake.tryMove is not a function
    at CheckForCollision (Collisions.js:3)
    at update (snake.js:453)
    at main (snake.js:391)

我无法在蛇形游戏中分离javascript文件

0 个答案: