Can you make an object 'callable'?

Question

Is it possible to make an object callable by implementing either call or apply on it, or in some other way? E.g.:

var obj = {};
obj         


        

Answer 1

No, but you can add properties onto a function, e.g.

function foo(){}
foo.myProperty = "whatever";

EDIT: to "make" an object callable, you'll still have to do the above, but it might look something like:

// Augments func with object's properties
function makeCallable(object, func){
    for(var prop in object){
        if(object.hasOwnProperty(prop)){
            func[prop] = object[prop];
        }
    }
}

And then you'd just use the "func" function instead of the object. Really all this method does is copy properties between two objects, but...it might help you.

Answer 2

ES6 has better solution for this now. If you create your objects in a different way (using class, extending 'Function' type), you can have a callable instance of it.

See also: How to extend Function with ES6 classes?

Answer 3

Others have provided the current answer ("no") and some workarounds. As far as first-class support in the future, I suggested this very thing to the es-discuss mailing list. The idea did not get very far that time around, but perhaps some additional interest would help get the idea moving again.

https://esdiscuss.org/topic/proposal-default-object-method

Answer 4

Following the same line of @Max, but using ES6 extensions to Object to pass all properties and prototype of an object obj to the callable func.

Object.assign(func, obj);
Object.setPrototypeOf(func, Object.getPrototypeOf(obj));