Question

I have a class, looks something like this:

function MyClass()
{
    this.array1 = [];
    this.array2 = [];
    this.add_item = function( i_x, i_y, i_item )
    {
        var pos = { "x" : i_x, "y" : i_y, "data" : i_item };
        this.array1.push( pos );
        this.array2.push( pos );
    }
    return this;
}

What is happening is that when I put a breakpoint at the second row of the add_item method (the this.array1.push row) both array1 and array2 already have the pos item! When I step forward one step, both arrays receive the pos item again!

The unlikely answer is that this is a bug in Firefox. I experimented a bit earlier with prototyping in methods into Object, but then read that that could lead to problems with for-each-loops. What could be causing this? Is the old code still bouncing around in there? I need a clue. I’ve removed all Array and Object prototype code I had. I’ve restarted firefox. Nothing helps. Any ideas?

Answer 1

It turns out the problem was with the firebug debugger. It was not showing the actual array. I’m not sure what it is showing, but I implemented my own object-printing-method (that handles cyclic object references) and it turns out the arrays are correct.

phew thought I was going nuts there for a while.