调用函数错误参数

Question

I'm trying to write a game and I got a problem with function showing player:

function Furry() {
  this.board=document.querySelectorAll('#board div');
  this.x = 0;
  this.y = 0;
  this.direction = "right";
}

and:

showFurry=function(){
  this.x = Math.floor(Math.random() * 10);
  this.y = Math.floor(Math.random() * 10);
  this.board[ this.position(this.furry.x , this.furry.y) ].classList.add('furry');
}

and in consol when I want to call function I got this:

Uncaught TypeError: Cannot read property 'x' of undefined

https://jsfiddle.net/mdx3w24c/

At this state after calling function showFurry and showCoin I should receive this:

Answer 1

Try removing the functions showFurry and showCoin . Then, make a function in the Game class that will do those things.

Game.prototype.start = function() {
    this.board[this.position(this.coin.x, this.coin.y)].classList.add('coin');
    this.board[this.position(this.furry.x, this.furry.y)].classList.add('furry');
};

Then when you start your game, instead of calling showFurry and showCoin you can call Game.start() ;

var game = new Game();
game.start();

Also your Coin constructor set random values to x & y, but the furry construct set them both to 0, then set them to random values in the showFurry function. In this fiddle, I've moved that to the constructor.