code-syle.js

function cls() {
    this.publicFunction1 = function () {
         return this._helperFunction1();
    };
    
    this._helperFunction1 = function (){};
    
    this.publicFunction2 = function () {
         return this._helperFunction2();
    };
    
    this._helperFunction2 = function (){};
}

// OR 

function cls() {
    this.publicFunction1 = function () {
         return this._helperFunction1();
    };
    
    this.publicFunction2 = function () {
         return this._helperFunction2();
    };
    
    this._helperFunction1 = function (){};

    this._helperFunction2 = function (){};
}