Finish module to allow json query to use shipping address postcode in Magento 2.2

We are adding a delivery calendar using the before-shipping-method-form using knockout. This part of the module is complete. We need somebody to complete this by adding the shipping address postcode to the json request.

The customer must be able to change this and the json request should update dynamically. The calendar should not display until the postcode is added to the Shipping Address. This is a small job for somebody with some spare time.