Can someone explain this small piece of javascript code to me?
<p>Basically I expect console.log to output 'yeah' but it doesn't. What can I do to make it output yeah without directly referencing it inside of <code>usefulFunction</code>?</p>

<pre><code>App = {
    config: {
        updateThis: 'false'
    },
    init: function(){
        this.usefulFunction(this.config.updateThis);
        this.consoleIt();
    },
    usefulFunction: function(item){
        item = 'yeah';
        // swap the above line for the line below and it works as expected
        // this.config.updateThis = 'yeah';
    },
    consoleIt: function(){
        console.log(this.config.updateThis);
    }
}

App.init();
</code></pre>
