Using the selectizeInput load(query, callback) configuration

I am looking to use the selectizeInput function to allow a user to search for an address using the google API, so when a user starts typing an address into a textbox, the selectizeInput function will then return a list of addresses s, very similar to the Google Maps address search box.
I have found notes on the selectize.js GitHub, possibly using the load(query, callback) option to call the Google API using Javascript. However, I am a complete novice with Javascript so unsure how to go about this, and even whether its possible using the Shiny implementation of selectize. Any feedback is much appreciated.