CODEWITHSUNDEEP
javascriptobjectprototypetypeerror
Jack Guy
Jack Guy

Reputation: 8523

JavaScript prototype structure and objects

I'm new to the prototype structure, and I'm having trouble figuring this one out. Here's my JavaScript code.

var Game = function ()
{
   //some variables
};
Game.prototype.block = 
{
    spawn: function () {
        var t1 = new this.inst;
    },
    inst : {
        x: 5,
        y: 0,
        type: ''
    }
};

When I try to create a new object "inst" I get the following error: TypeError: object is not a function. What am I doing incorrectly?

Upvotes: 0

Views: 640

Answers (3)

I Hate Lazy
I Hate Lazy

Reputation: 48761

If you want to create objects that inherit from the inst object, you can do that using Object.create, with var t1 = Object.create(this.inst);.

var Game = function () {
   //some variables
};
Game.prototype.block =  {
    spawn: function () {
        var t1 = Object.create(this.inst);
    },
    inst : {
        x: 5,
        y: 0,
        type: ''
    }
};

So then your code would look something like this;

var game = new Game();

game.block.spawn();

And the .spawn() method would have a variable that references an object that inherits from the Game.prototype.block.inst object.

Upvotes: 1

Shuping
Shuping

Reputation: 5458

I guest you need a static factory method to create new "inst". is the below code what you need? you call the Game.spawn method to generate a new inst, and you can put this method in setInterval.

function Game() {
    //some variables
}

Game.spawn = function() {
    function Inst() {
        this.x = 5;
        this.y = 0;
        this.type = '';
    }

    return new Inst;
}

var inst1 = Game.spawn();
inst1.x = 1; //test inst1
console.log(inst1.x);
var inst2 = Game.spawn();
inst2.x = 2; //test inst2
console.log(inst2.x);
var inst3 = Game.spawn();
inst3.x = 3; //test inst 3
console.log(inst3.x);

Upvotes: 0

Milad Naseri
Milad Naseri

Reputation: 4118

First of all, inst is not defined within the scope of Game. So, this which refers to Game doesn't have any properties called inst. Secondly, inst must be followed by () to indicate a call to the constructor, which you are missing here.

Upvotes: 0

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