Javascript - create a new bullet instance every time a user event is triggered

Question

Basically I have a function that I need to create an object of every time the user presses space(event listeners not shown here).

function arrow(){
    this.x = playerXPos + 40;
    this.y = playerYPos + 40;

    this.init = function(){
        var arrowImg = new Image();
        arrowImg.src = "arrow.png";
        c.drawImage(arrowImg,this.x,this.y);

        this.x+=10;

        if(this.x > 500){
            keySpace = false;
        }
    }
}

if(keySpace){
    arrowObj.init();
}

This works great, but I can only have 1 arrow on the screen at once, which is rather limiting. Is there some way to create a new object every time the if statement is true, and store it in an array or something?

Answer 1

You can use new to create a new object, initialize it and then store it in an array

// declare this array in a scope that persists (e.g. global scope or in a closure)
var arrows = [];

if(keySpace){
    // create new arrow, initialize it and store it in the array of arrows
    var newArrow = new arrow();
    newArrow.init();
    arrows.push(newArrow);
}

Answer 2

You could also do more or less the same thing, but alocate a fixed size array from start and then just fetch one that isent in use. This is much more memory friendly.

this is called memory pools.