Question

I’m trying to remove the eval statement in this function. I’m used to the this[whatever] style replacement but it doesn’t work out in this instance.
Have a look:

var App = (function(fw) {
    var somevar1 = "hello";
    var somevar2 = "world";
    this.get = function(what) {
        return eval(what);
    }
});

var app = new App({some: "thing"});

// now for the use:
console.log(app.get("somevar1"),app);​

In the function, all my normal “eval scrubbing” options are not working for instance, I cant use:

 return this[what]
 return [what]
 return app[what]
 return new Function(what);

surely this isn’t an odd case where eval is necessary? .. ps I have to note that I CANNOT rescope the variables inside App as it’s part of a huge codebase.

Here’s something to fiddle with:

http://jsfiddle.net/xAVYa/

Answer 1

Unfortunately, you’re out of luck; eval is the only thing that can access variables like that. Next time, don’t do things that way 🙂

You can start a migration by keeping a data object:

var App = (function(fw) {
    var data = {
        somevar1: "hello",
        somevar2: "world"
    };

    this.get = function(what) {
        return data[what];
    };
});

And just gradually do this across the entire codebase where you see it. It shouldn’t break anything.