Validating form fields on Lightning Aura component

validateController.js

var page1ReqFields = ['lastName','firstName','prefix','birthDate','gender','homePhnNum','pmAddres','pmCity','pmState','pmZip']; 
// aura Ids of required fields 

validateHelper.js

/* Validate required fields */
    validateReqFields: function(component, event,ReqFields) {
        component.set('v.validateReqFields',false);
        var i;
        for(i in ReqFields){
            var value = component.find(ReqFields[i]).get("v.value");
            var validityVal = component.find(ReqFields[i]).get("v.validity").valid;
            if((value == "" || value == null ) && validityVal != true){
                component.find(ReqFields[i]).reportValidity();
                component.set('v.validateReqFields',true);
                component.set('v.dispReqFieldError',true);
                console.log('dispReqFieldError',component.get('v.dispReqFieldError'));
            }
        }
        window.scrollTo(0, 0);
    },