Creating a function from string which inherits the parent scope

Question

In Javascript, is there a way to create a function from a string (such as through the new Function() constructor) and have it inherit the parent scope? For example:

(function(){
    function yay(){
    }
    var blah = "super yay"
    yay.prototype.testy = new Function("alert(blah)")
    yay.prototype.hello = function(){alert(blah)}
    whee = new yay();
    whee.hello()
    whee.testy()
})()

Is there any way to make whee.testy() also alert "super yay"?

Answer 1

Actually, combining function and eval should do what you want:

// blah exists inside the 'hello' function
yay.prototype.hello = function(){ alert(blah) }
// blah also exists inside the 'testy' function, and
// is therefore accessible to eval().
yay.prototype.testy = function(){ eval('alert(blah)') }

Answer 2

(function(){
    function yay(){
    }
    var blah = "super yay"
    yay.prototype.testy = eval("(function(){alert(blah)})")//new Function("alert(blah)")
    yay.prototype.hello = function(){alert(blah)}
    whee = new yay();
    whee.hello()
    whee.testy()
})()

This seems to work for me, and none of the eval'd data is from any untrusted source. It's just to be used for minifying code.