TYpescript : Static methods on Function as class - class

Question

I have a fn that inherit an existing fn ( take Angular1 $q for example )
//$q original behavior
var defer = $q.defer();
defer.promise.then(function(result){})
//or
$q( (resolve, reject) => {
//promise execution here
}).then(function(result){});
If I want to decorate it, I would do :
var Qdecorator = function($delegate) {
var Q = function(resolver:any): any {
//do some extra stuff here
return $delegate.apply($delegate, arguments);
}
//Assign the static methods here:
Q.defer = function() {
//do some stuff
return $delegate.defer.apply($delegate, []);
}
//same goes for race, when, resole reject and so on
return Q;
}
Problem is that typescript complains about
Property defer, race, when, resolve, etc... does not exist on type '(resolver: any) => any'
I tried to use the IQService, and IPromise with no luck, btu I'd like to raise a more global question :
How do I define late static methods on function() that return an object without using new

Answer 1

I am copying pasting the answer to my question from this link:
https://www.typescriptlang.org/docs/handbook/interfaces.html
interface Counter {
(start: number): string;
interval: number;
reset(): void;
}
function getCounter(): Counter {
let counter = <Counter>function (start: number) { };
counter.interval = 123;
counter.reset = function () { };
return counter;
}
let c = getCounter();
c(10);
c.reset();
c.interval = 5.0;