I have an application that uses callback functions that alter properties of an object, example
Code:
function app()
{
    this.attributes = {
		"a": 100,
		"b": 100,
		"c": 100,
		"d": 100,
		"e": 100,
		"f": 100
	};
}
my callback functions look like this
Code:
function()
{
	this.attributes["x"] = (this.attributes["x"] || 0) + 100;
}
I would like to write it as
Code:
function()
{
	this.attributes["x"] += 100;
}
I know you can use Object.prototype.__proto__ to redefine default values for properties (from null to 0). but does this apply to non-existent properties as well?