I've Heard Global Variables Are Bad, What Alternative Solution Should I Use?

Question

I\'ve read all over the place that global variables are bad and alternatives should be used. In Javascript specifically, what solution should I choose.

I\'m thinking

Answer 1

Semantics my boy. Semantics.

Start with one global: myApp = {}; Everything should be in that. The only exception would be your AJAX library (there are some extreme exceptions like working with JSONP callbacks).

There should be very few properties in myApp. You'll want to hold your application properties in containers such as config or settings.

myApp = {
    config:{
        prop:1
    },
    settings:{
        prop:2
    },
    widgets:{
        List: function(props){},
        Item: function(props){}
    }
}

Then you may have more properties in lower modules, components, singletons and Class constructors (widgets).

This setup gives you the added benefit of being able to access any property from any other location since you can get it with the myApp global. However, you should use "this" whenever possible because the lookup is faster. And just set the property directly, don't bother with the pseudo getter/setter stuff. If you really need a getter/setter, code it for that specific use.

The reason your example doesn't work is it's too generic and you seem to be looking for an excuse to work in the global space.

And don't get clever with private variables. They're bad too: http://clubajax.org/javascript-private-variables-are-evil/