SOURCE

var myMethods = {};
;(function(){
    function ConsFunc(){}
    Object.assign(ConsFunc.prototype,{
        a1(){
           console.log('a1'); 
        },
        a2(){
            console.log('a2');
        }
    });
    myMethods.ConsFunc = ConsFunc;
})();

var fn1 = new myMethods.ConsFunc();
fn1.a1();
fn1.a2();