ES6 arrow function syntax

ES6_arrow_function_syntax.js

// You can check this with Google Traceur Compiller
// http://code.google.com/p/traceur-compiler/

class Test {
    constructor(){
	var self = this,
            fn = () => this === self,
            fnOld = function(){ return this === self };
        console.log( 'fn', fn(), 'fnOld', fnOld() );
    }
}
var test = new Test();

/*
    Console shows:
    "fn" true "fnOld" false

    I think this awful - else one ambiguous place in JS, it can eat many-many 
    time to investigate that behaviour of 'fn' and 'fnOld' is different.
    
    http://wiki.ecmascript.org/doku.php?id=harmony:arrow_function_syntax
*/