instantiate dynamic class

Question

In Javascript, how do you instantiate a new class dynamically without using eval() and pass in an argument? For example, let's say I want to create a new CatViewController and pass in "kitten", how would I do that?

var myClassname = "CatViewController";
var cat = new myClassname("kitten");

It should resolve to:

var cat = new CatViewController("kitten");

Thanks!

Answer 1

As long as the function is within scope you can do this:

var cat = new this[myClassname]("kitten");

Another similar way:

var classes = {
    A: function (arg) {

    },
    B: function (arg) {

    },
    C: function (arg) {

    }
};

var a = new classes["A"]("arg");