I would recommend using JSON.stringify, which converts the set of the variables in the object to a JSON string.

var obj = {
  name: 'myObj'
};

JSON.stringify(obj);

Most modern browsers support this method natively, but for those that don't, you can include a JS version.

Actually, the best solution is using JSON:

Documentation

JSON.parse(text[, reviver]);

Examples:

1)

var myobj = JSON.parse('{ "hello":"world" }');
alert(myobj.hello); // 'world'

2)

var myobj = JSON.parse(JSON.stringify({
    hello: "world"
});
alert(myobj.hello); // 'world'

3) Passing a function to JSON

var obj = {
    hello: "World",
    sayHello: (function() {
        console.log("I say Hello!");
    }).toString()
};
var myobj = JSON.parse(JSON.stringify(obj));
myobj.sayHello = new Function("return ("+myobj.sayHello+")")();
myobj.sayHello();

JavaScript has two main type categories, primitives and objects.

var s = 'test';
var ss = new String('test');

The single quote/double quote patterns are identical in terms of functionality. That aside, the behaviour you are trying to name is called auto-boxing. So what actually happens is that a primitive is converted to its wrapper type when a method of the wrapper type is invoked. Put simple:

var s = 'test';

Is a primitive data type. It has no methods, it is nothing more than a pointer to a raw data memory reference, which explains the much faster random access speed.

So what happens when you do s.charAt(i) for instance?

Since s is not an instance of String, JavaScript will auto-box s, which has typeof string to its wrapper type, String, with typeof object or more precisely s.valueOf(s).prototype.toString.call = [object String].

The auto-boxing behaviour casts s back and forth to its wrapper type as needed, but the standard operations are incredibly fast since you are dealing with a simpler data type. However auto-boxing and Object.prototype.valueOf have different effects.

If you want to force the auto-boxing or to cast a primitive to its wrapper type, you can use Object.prototype.valueOf, but the behaviour is different. Based on a wide variety of test scenarios auto-boxing only applies the 'required' methods, without altering the primitive nature of the variable. Which is why you get better speed.

Speaking about language types, Strings are values of the String type.

The language has five primitive types, which are String, Number, Boolean, Null and Undefined.

There are String objects (also for Number or Boolean), they are called primitive wrappers, they are created when you use the constructor function associated with them, for example:

typeof new String('foo'); // "object"
typeof 'foo';             // "string"

But don't get confused with them, you will rarely need to use primitive wrappers, because even if primitive values are not objects, you can still access their inherited properties, for example, on a string, you can access all members of String.prototype, e.g.:

'foo'.indexOf('o'); // 2

That's because the property accessor (the dot in this case) temporarily converts the primitive value to an object, for being able to resolve the indexOf property up in the prototype chain.

About the constructor function you have in your question, as you know, it won't return the string.

Functions called with the new operator return an implicit value, which is a new object that inherits from that function's prototype, for example:

function Test () {
  // don't return anything (equivalent to returning undefined)
}

new Test() instanceof Test; // true, an object

If an object is returned from the constructor, that newly created object (this within the constructor) will be lost, so the explicit returned object will come out the function:

function Test2() {
  return {foo: 'bar'};
}

new Test2().foo; // 'bar'

But in the case of primitive values, they are just ignored, and the new object from the constructor is implicitly returned (for more details check the [[Construct]] internal operation, (see step 9 and 10)).