This filter allows you to include additional meta data in the JSON response on the front end.
$store_fields - (array) The fields that hold the existing store data.
This example shows how to make data from the wpsl_my_textinput meta field accessible in the JSON response under the my_textinput key.
This filter is located in /frontend/class-frontend.php.
The code needs to be placed in the functions.php file inside your active theme folder.