Use of the identity function in JavaScript

I use the identity function in all my JavaScript programs:

function identity(value) {    return value;}

The reason is that I often need differentiate between primitives types (undefined, null, boolean, number and string) and object types (object and function) as returned by the typeof operator. I feel using the indentity function for this use case very succuint:

if (new identity(value) == value); // value is of an object typeif (new identity(value) != value); // value is of a primitive type

The identity function is much smaller and simpler than the following code:

function isObject(value) {    var type = typeof value;    return type == "object" || type == "function";}

However on reading my code a friend of mine complained that my hack is misleading and more computationally expensive than the above alternative.

I don't want to remove this function from any of my programs as I believe it's an elegant hack. Then again I don't write programs solely for myself. Is there any other use case for the identity function in JavaScript?