Question

I’d like to augment the Function object to do more operations while constructing a new object.
Is it possible?

Answer 1

There is no way to modify the Function prototype so that you can intercept calls to a function. The closest you are going to get to this is to add a method that you can call in place of a constructor. For example:

Function.prototype.create = function() {
    var obj = new this();  // instantiate the object
    this.apply(obj, arguments);  // call the constructor

    // do your stuff here (e.g. add properties or whatever it is you wanted to do)
    obj.foo = 'bar';

    return obj;
};

function SomeObject(name) {
    this.name = name;
}

var obj = SomeObject.create('Bob');
obj.foo; // => 'bar'

Alternatively you could write a function that you would call to build a constructor:

Function.makeConstructor = function(fn) {
    return function proxyConstructor() {
        // check to see if they called the function with the "new" operator
        if(this instanceof proxyConstructor) {
            var obj = new fn();
            fn.apply(obj, arguments);

            // do your stuff here (e.g. add properties or whatever it is you wanted to do)
            obj.foo = 'bar';

            return obj;
        } else {
            return fn.apply(null, arguments);
        }
    };
};

var SomeObject = Function.makeConstructor(function(name) {
    this.name = name;
});

var obj = SomeObject.create('Bob');
obj.foo; // => 'bar'