How do I pass an array to a class witch is under the influence of keys as a parameter? ES6

Question

Hi if I try to pass an array to a class function as a parameter it workes fine. try it in this snippet of code:

class boo {
    moo() {
        this.bob = [false, "Bob"];
        this.kees = [false, "Kees"];
    }

    doo() {
        this.bob = [true, "Bob"];
        this.kees = [true, "Kees"];
    }
}

class foo {
    constructor() {
        this.hi = [];
    }
    lala(arg) {
        let bool = arg[0];
        let string = arg[1];
        if (bool && !this.hi[string]) {
            this.hi[string] = true;
            return string + " is true"
        }
        return string + " is true - will be entered one time not multiple";
    }

    dada(arg) {
        let bool = arg[0];
        let string = arg[1];
        if (!bool && this.hi[string]) {
            this.hi[string] = false;
            return string + " is false";
        }
        return string + " is false - will be entered one time not multiple";
    }
}

objBoo = new boo();
objFoo = new foo();

objBoo.doo();
console.log(objFoo.lala(objBoo.bob));
console.log(objFoo.lala(objBoo.bob));
console.log(objFoo.lala(objBoo.kees));
objBoo.moo();
console.log(objFoo.dada(objBoo.bob));
console.log(objFoo.dada(objBoo.kees));
console.log(objFoo.dada(objBoo.kees));

So what is the problem in this code snippet? I can not figure it out by my self. I feel like it has something to do with this question: How to access the correct this inside a callback?

/*ignore pls*/class BehaviourClass {
/*ignore pls*/    constructor() {
/*ignore pls*/        this.start = true;
/*ignore pls*/    }
/*ignore pls*/
/*ignore pls*/    Awake() {
/*ignore pls*/        window.AnimationFrame();
/*ignore pls*/    }
/*ignore pls*/}

//like the boo class where it works fine;
class KeyCodeClass {
    KeyDown(e) {
        //spacebar
        if (e.keyCode == 32) { this.Space = [true, "Space"] }
    }

    KeyUp(e) {
        //spacebar
        if (e.keyCode == 32) { this.Space = [false, "Space"] }
    }
}

//like the foo class where it works fine
class InputClass {
    constructor() {
        this.pressed = [];
    }

    GetKeyDown(arg) {
        let bool = arg[0];
        let string = arg[1];
        if (bool && !this.pressed[string]) {
            this.pressed[string] = true;
            return true;
        }
        if (!bool && this.pressed[string]) {
            this.pressed[string] = false;
            return false;
        }
    }

    GetKeyUp(arg) {
        let bool = arg[0];
        let string = arg[1];
        if (bool && !this.pressed[string]) {
            this.pressed[string] = true;
            return false;
        }
        if (!bool && this.pressed[string]) {
            this.pressed[string] = false;
            return true;
        }
    }
}

/*ignore pls*/var Behaviour = new BehaviourClass();
var KeyCode = new KeyCodeClass();
var Input = new InputClass();

//controles if a key is pressed
window.addEventListener("keydown", KeyCode.KeyDown.bind(KeyCode), false);
window.addEventListener("keyup", KeyCode.KeyUp.bind(KeyCode), false);

/*ignore pls*/function AnimationFrame() {
/*ignore pls*/    Update();
/*ignore pls*/    requestAnimationFrame(AnimationFrame);
/*ignore pls*/}

function Update() {
    if(Input.GetKeyDown(KeyCode.Space)) {
        console.log("spacebar down");
    }
    if(Input.GetKeyUp(KeyCode.Space)) {
        console.log("spacebar up");
    }
}

/*ignore pls*/Behaviour.Awake();

I get the error arg is undefined by the second snippet. But in the class foo from the first snippet works fine. Can someone explain what I do wrong. The snippets are in my opinion almost the same.

@DaveNewton I chance the value KeyCode.Space by pressing the spacebar in that way invulensed bij key. — TessavWalstijn, Feb 27 '17 at 17:09
@RensvWalstijn I was mostly asking what the words "invulensed" and "bij" meant; I think there's a translation issue. — Dave Newton, Feb 27 '17 at 17:16
@DaveNewton "under the influence of keys" I will edit the question I read "bij" I undersrand the translation issue thx! — TessavWalstijn, Feb 27 '17 at 17:28

score 0 · Accepted Answer · answered Feb 24 '17 at 18:28

KeyCode.Space is not defined in your code, so the value of KeyCode.Space is undefined and when you call the function Input.GetKeyDown(KeyCode.Space) the argument is passed as undefined.

Next, in the function GetKeyDown(arg), the arg would be undefined and when you are trying to find the element at 0th index by using the statement let bool = arg[0]; it throws an error

TypeError: Cannot read property '0' of undefined

So, define the value for the KeyCode.Space in your code and also write the gaurd condition before proceeding ahead in the function. If the condition fails, then return.

Oh thanks! I need to use the constructor and devinde `this.Space = [];` To long looking at the problem -,- — TessavWalstijn, Feb 24 '17 at 20:09

How do I pass an array to a class witch is under the influence of keys as a parameter? ES6

1 Answers1