How to get instance of the membership class in pure javascript?

I have this class created in pure JavaScript:

var MapInteraction = function () {

return {
    handleNavigation: handleNavigation,
    handleMapDrawing: handleMapDrawing,
    handleMapData: handleMapData
};

//controls map interactions
function handleNavigation() {

    //some code
}

function handleMapDrawing() {

    //some code
}

function handleMapData() {

    //some code
}

};

Here is how I creaet instance of the class:

var mapInteraction = new MapInteraction();

at some point, I want to iterate on MapInteraction functions and to get the instance of each member. Here how I do it:

 mapInteraction.forEach((interaction, interactionType) => { 
            if (interaction instanceof interactionToEnable)
            {
                //do something
            }
        });

But on the row above I get this error(I understand that I can't use foreach because it suitable only for arrays):

Uncaught TypeError: mapInteraction.forEach is not a function

My question is how can iterate on MapInteraction functions and to get an instance of each member?