Call nested functions from external js file

Question

I have to use an external js file in my TS component that it's like this:

var myObj;

function setObj(newObj) {
    myObj= newObj;
    return myObj;
}

function my_object() {
    this.getA= function () {
        return this.A;
    }

    this.getB= function () {
        return this.B;
    }

    this.getC = function () {
        return this.C;
    }
}

I am able to call the function setObj after declaring it this way in my.ts file:

declare function setObj(obj: MyObj);

But I need to call also the other functions (getA, getB, getC), but I don't know how.
I've tried returning the object when calling setObj and then call the function, like this:

let objReturned = setObj(myObj);
objReturned.getA()

but it tells me that getA is not a function.
How can I call these nested functions inside the js?

Answer 1

You'll want something like:

declare interface SetObjC {
    getC: () => void;
}
declare interface SetObjB {
    getB: () => SetObjC
}
declare interface SetObjA {
    getA: () => SetObjB;
}
declare function setObj(obj: MyObj): SetObjA;