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JavaScript Object-Oriented JavaScript: Challenge Rendering the Game startGame() Method Solution

Hamzah Iqbal
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.a{fill-rule:evenodd;}techdegree
Hamzah Iqbal
Full Stack JavaScript Techdegree Student 11,145 Points

Game.js:34 Uncaught TypeError: Cannot read property 'drawHTMLToken' of undefined

class Game {


    constructor() {

        this.board = new Board();
        this.players = this.createPlayers();
        this.ready = false;
    }

    /**
     *  * Creates two player objects
 *        @return  {Array}    An array of two Player objects.
     * 
     * 
     * */

    createPlayers() {

        const players = [new Player("Player1", 1, "#e15258", true),
        new Player("Player 2", 2, "#e59a13")];




        return players;
    }

    /* makes game ready to play 
    */
    startGame() {

        this.board.drawHTMLBoard();
        this.activePlayer.activeToken.drawHTMLToken();
        this.ready = true;

    }

    get activePlayer() {
        return this.players.find(player => player.active);



    }


}
class Player {

    constructor(name, id, color, active = false) {
        this.name = name;
        this.id = id;
        this.color = color;
        this.active = active;
        this.token = this.createTokens(21);


    }

    /**
     * 
     * @param {integer} num - number of objects to be created
     */
    createTokens(num) {
        const tokens = [];

        for (i = 0; i < num; i++) {

            let token = new Token();
            tokens.push(token);


        }

        return tokens;


    }

    get unusedTokens() {
        return this.tokens.filter(token => !token.dropped);
    }


    get activeToken() {
        return this.unusedTokens[0];
    }


}
class Token {

    constructor(owner, index) {
        this.owner = owner;
        this.id = `token-$-{index}-$-{owner.id}`;
        this.dropped = false;

    }

    drawHTMLToken() {



        const div = document.createElement("div");
        document.getElementById("game-board-underlay").appendChild(div);
            div.setAttribute("id", this.id);
            div.setAttribute("class", "token");

            div.style.backgroundColor = this.owner.color;





    }



}
class Board {

    constructor() {

        this.rows = 6;
        this.columns = 7;
        this.spaces = this.createSpaces();



    }



    createSpaces() {

       const spaces = [];
        for (var x = 0; x < this.rows; x++) {
            const rows = [];

            for (var y = 0; y < this.columns; y++) {

                const space = new Space(x, y);
                rows.push(space);

            }


            spaces.push(rows);


        }


        return spaces;

    }

    drawHTMLBoard() {
        for (let column of this.spaces) {
            for (let space of column) {
                space.drawSVGSpace();
            }
        }
    } 

}
class Space {
    constructor(x, y, diameter, radius) {
        this.x = x;
        this.y = y;
        this.id = `space-${x}-${y}`;
        this.token = null;
        this.diameter = 76;
        this.radius = this.diameter / 2;




    }

    drawSVGSpace() {

        const svgSpace = document.createElementNS("http://www.w3.org/2000/svg", "circle");
        svgSpace.setAttributeNS(null, "id", this.id);
        svgSpace.setAttributeNS(null, "cx", (this.x * this.diameter) + this.radius);
        svgSpace.setAttributeNS(null, "cy", (this.y * this.diameter) + this.radius);
        svgSpace.setAttributeNS(null, "r", this.radius - 8);
        svgSpace.setAttributeNS(null, "fill", "black");
        svgSpace.setAttributeNS(null, "stroke", "none");
        document.getElementById("mask").appendChild(svgSpace);   




    }







}

app.js

const newGame = new Game();
document.querySelector("#begin-game").addEventListener("click", function () {

    //calls startgame on the game object initalized


    newGame.startGame();

    this.style.display = "none";
    document.getElementById('play-area').style.opacity = '1';




});
Jenner Thomas
Jenner Thomas
8,210 Points

In your "get Unusedtokens" method, in the Player class, your return call is using the incorrect name for the 'token' property. You have 'this.token' as the property name in your constructor.

1 Answer

Steven Parker
Steven Parker
231,271 Points

As Jenner observed, the "token" (singlular) property in the Player class is being referred to as "tokens" (plural) in the "unusedTokens" method.

And for future questions, make a snapshot of your workspace and post the link to it here to facilitate easy replication of the issue (and to save a lot of space in the question!).