Immutable.js

var __extends = this.__extends || function (d, b) {
    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
    function __() { this.constructor = d; }
    __.prototype = b.prototype;
    d.prototype = new __();
};
var Immutable = (function () {
    function Immutable() {
        this.objectString = "object";
    }
    Immutable.prototype.Freeze = function () {
        Object.freeze(this);
        return this;
    };

    Immutable.prototype.copy = function (obj) {
        var copy;
        var toCopy = obj || toCopy;
        if (toCopy instanceof Array) {
            copy = [];
        } else {
            copy = {};
        }
        var keys = Object.keys(toCopy);
        for (var i = 0; i < keys.length; i++) {
            if (typeof toCopy[keys[i]] !== this.objectString) {
                copy[keys[i]] = toCopy[keys[i]];
            } else {
                copy[keys[i]] = this.copy(toCopy[keys[i]]);
            }
        }
        return copy;
    };

    Immutable.prototype.Copy = function (obj) {
        return this.copy(obj || this);
        ;
    };
    return Immutable;
})();

Immutable.ts

interface IImmuatable {
	Freeze: () => IImmuatable;
	Copy: <T>(obj: any) => T;
}

class Immutable implements IImmuatable{
	private objectString = "object";
	
	public Freeze () {
		Object.freeze(this);
		return this;
	}
	
	private copy(obj? : IImmuatable) {
		var copy;
		var toCopy = obj || toCopy;
		if(toCopy instanceof Array){
			copy = [];
		} else {
			copy = {};
		}
		var keys = Object.keys(toCopy);
		for(var i = 0; i < keys.length; i++){
			if(typeof toCopy[keys[i]] !== this.objectString){
				copy[keys[i]] = toCopy[keys[i]];
			} else {
				copy[keys[i]] = this.copy(toCopy[keys[i]]);
			}
		}
		return copy;
	}
	
	public Copy<T> (obj?: Immutable): T {		
		return <T>this.copy(obj || this);;
	}
}

tests.js

var Person = (function (_super) {
    __extends(Person, _super);
    function Person(Name) {
        _super.call(this);
        this.Name = Name;
    }
    return Person;
})(Immutable);

var p = new Person("Adam");
p.Freeze();
console.assert(p.Name === "Adam");
p.Name = "Derp";
console.assert(p.Name === "Adam");


var q = p.Copy<Person>(); //Create a copy of the Object , the copy should not be frozen. 
console.assert(q.Name === "Adam"); //should keep it's old values.
q.Name = "Derp"; // should now be another value, despite having Freeze called on it's source.
console.log(q.Name === "Derp");