How to use region updater in magento 2 custom module?

Question

I am working on the region updater in magento 2. Region Field needs to change based on the selection of country. Below is my region updater code:

 var billingRegionUpdater = new RegionUpdater('#country', '#region_id',
 '#region', <?php /* @escapeNotVerified */ echo
 $this->helper('Magento\Directory\Helper\Data')->getRegionJson() ?>,
 undefined, '#zip');

After updating the above code, I am getting the following error,

TypeError: this.options.regionJson is undefined http://magento-dev.com/pub/static/version1495188452/frontend/Rosetta/mpw/en_US/Magento_Checkout/js/region-updater.js Line 233

Can someone help me to rectify this issue?

Thanks!!!