How to use Button Set to highlight the field value from REST

Summary

How to use Button Set to highlight the field value from REST

Content

Hi,

We have requirement to show two flag icons(red & Green button) on UI and it is tied to a single boolean field from REST API.

In the VBCS application we want to tie the data from the boolean field from REST API with the button set such that if the Field is Y then highlight Green button. if the Flag value is N then highlight Red Button.

If user click on Red button then set the field value to Y . if User click on Green button then set the field value to N. To achieve this we have written below code. But it is not working at all. Infact we are getting blank screen after adding this code.