Sanitize custom field checkbox option

If I’m not mistaken, for the default checkbox stuff we have in CMB2, it’s either an empty value or “on” for a value. Are you doing something similar to that for values?

Yes:

    $value          = wp_parse_args( $value, array(
        'id'        => '',
        'label'     => '',
        'type'      => 'text',
        'options'   => '',
        'size'      => '',
        'required'  => 'on' // this is checkbox
    ) );

But when i deselect the checkbox, the field remains checked after save post.

My solution, this is not best solution, but solved =(

Sanitize checkbox:

        if ( empty($val['required']) ):
            unset( $val['required'] );
            $val['required'] = 'off';
        else:
            $val['required'] = 'on';
        endif;

In my js:

jQuery(function ($){
   $(".form_field_required input[type='checkbox']").each(function (){
      if($(this).val() !== 'on'){
          $(this).removeAttr('checked');
      }
   });
});