trying avoid memory leaks

hi, i just finished read this article about avoid memory leaks: https://wiki.appcelerator.org/display/guides2/Managing+Memory+and+Finding+Leaks in my application i have a few libraries that exports windows or pickers. like example: controluicombobywin.js

function controlUiComboByWin(indata, sdata, callback,refWindow, refId, pickerRef,callbackChangeVal) {
    callbackChangeVal = callbackChangeVal || null;
    var searchs = require('/lib/searchs');  
    this.id = refId;
    this.dataCbx = indata;
    var that = this;
    var containerPicker = Ti.UI.createView({
        width: sdata.listViewWidth,
        height:Ti.UI.SIZE,
        top: sdata.pickerTop,
        touchEnabled: true,
        bubbleParent:true,
        backgroundColor:'#FFFFFF',
        borderColor:'#DAD6DA',
        borderWidth : 1,
    });
    if(sdata.orientation == 'right'){
        containerPicker.right = sdata.pickerPosition;
    }else if(sdata.orientation == 'left'){
        containerPicker.left = sdata.pickerPosition;
    }else{
        containerPicker.center = sdata.pickerPosition;
    }
    var picker = Ti.UI.createTextField({
        color: '#817F81',
        value: sdata.valuePicker,
        editable: false,
        touchEnabled: true,
        font: {
            fontSize: sdata.fontSize,
            fontFamily: sdata.fontFamily
        },      
        left: '0dp',
        width:'80%',
        height:'100%',
        wordWrap:true,
        textAlign:'left',
        verticalAlign: Ti.UI.TEXT_VERTICAL_ALIGNMENT_CENTER,
        backgroundColor:'transparent',  
        borderRadius:3,  
        backgroundPaddingLeft: 30,
        backgroundPaddingRight: 30
    });
    imageSpin = Ti.UI.createImageView({
        image:'/images/spin.png',
        right: '7dp',
        touchEnabled: true,
        width:'20dp',
        height:'20dp'
    });
    containerPicker.add(imageSpin);
    containerPicker.add(picker);
    containerPicker.addEventListener('click',function(e){
        e.bubbles = true;
        try{
            var modal = require('/lib/modalWindows').modalWin;
            containerPicker.setBorderColor('#DAD6DA');
            var arrdata = that.dataCbx;
            var tools   = new searchs.Tools();
            var sizeWin = tools.calculateWidthWin(20);
            var popupWin = new modal(arrdata, sdata, picker, "picker","80%", sizeWin, null, null, that,callbackChangeVal);
            var _deviceE = tools.osDevice();
            if(_deviceE == "android")
                popupWin.open({activityEnterAnimation: Ti.Android.R.anim.fade_in, activityExitAnimation:  Ti.Android.R.anim.fade_out, modal: true});
            else
                popupWin.open({modal: true});
            modal = null;
            arrdata = null;
            tools = null;
            sizeWin = null;
            popupWin = null;
            _deviceE = null;
        }catch(e){
            tools.nativeNotification(L('errorAction'));
        };
    });
    picker.addEventListener('change', function(e){
        e.bubbles = true;
        if(pickerRef){
            if(callback){
                var data = callback(that.id);
                pickerRef.changeValueRef('');
                pickerRef.setdataCbx('');
                pickerRef.dataCbx = data;
                pickerRef.id = data[0].id;
                pickerRef.setrefId(data[0].id);
                pickerRef.statusChange();
            }
        }
    });
    refWindow.add(containerPicker);
    this.changeValueRef = function(value) {//change value name
        picker.value = value;   
    };
    this.GetID = function(value){
        return this.id;
    };
    this.openWin = function(){
        try{
            containerPicker.setBorderColor('#DAD6DA');
            var modal = require('/lib/modalWindows').modalWin;
            var arrdata = that.dataCbx;
            var tools   = new searchs.Tools();
            var _deviceE = tools.osDevice();
            var sizeWin = tools.calculateWidthWin(20);
            var popupWin = new modal(arrdata, sdata, picker, "picker","80%", sizeWin, null, null, that,callbackChangeVal);
            if(_deviceE == "android")
                popupWin.open({activityEnterAnimation: Ti.Android.R.anim.fade_in, activityExitAnimation:  Ti.Android.R.anim.fade_out, modal: true});
            else
                popupWin.open({modal: true});
        }catch(e){
            tools.nativeNotification(L('errorAction'));
        };
    };
    this.refValue = function(){
        return picker.value;
    };
    this.changeStatus = function(){
        containerPicker.setBorderColor('#FF2626');
    };
}
function getdataCbx(){
    return this.dataCbx;
}
function setdataCbx(data){
    this.dataCbx = data;
}
function getrefId(){
    return this.id;
}
function setrefId(id){
    this.id = id;
}
function setText(name){
    this.changeValueRef(name);
}
function showWin(){
    this.openWin();
};
function getrefValue(){
    return this.refValue();
};
function statusChange(){
    this.changeStatus();
};
controlUiComboByWin.prototype.showWin = showWin;
controlUiComboByWin.prototype.setText = setText;
controlUiComboByWin.prototype.getdataCbx = getdataCbx;
controlUiComboByWin.prototype.setdataCbx = setdataCbx;
controlUiComboByWin.prototype.getrefId = getrefId;
controlUiComboByWin.prototype.setrefId = setrefId;
controlUiComboByWin.prototype.statusChange = statusChange;
controlUiComboByWin.prototype.getrefValue = getrefValue;
module.exports = controlUiComboByWin;

in each function that references objects once time its not used i must assigned null value? like:

e.bubbles = true;
        try{
            var modal = require('/lib/modalWindows').modalWin;
            containerPicker.setBorderColor('#DAD6DA');
            var arrdata = that.dataCbx;
            var tools   = new searchs.Tools();
            var sizeWin = tools.calculateWidthWin(20);
            var popupWin = new modal(arrdata, sdata, picker, "picker","80%", sizeWin, null, null, that,callbackChangeVal);
            var _deviceE = tools.osDevice();
            if(_deviceE == "android")
                popupWin.open({activityEnterAnimation: Ti.Android.R.anim.fade_in, activityExitAnimation:  Ti.Android.R.anim.fade_out, modal: true});
            else
                popupWin.open({modal: true});
            modal = null;
            arrdata = null;
            tools = null;
            sizeWin = null;
            popupWin = null;
            _deviceE = null;
        }catch(e){
            tools.nativeNotification(L('errorAction'));
        };

is that correct or is another way to avoid memory leaks? thanks in advance