separate-with-spaces.php

<?php

add_filter( 'jet-form-builder/content-filters', function( $filters ) {

        class Separate_With_Spaces_JFB_Filter extends \Jet_Form_Builder\Classes\Filters\Base_Filter {

                public function get_id(): string {
                        return 'separate_with_spaces';
                }

                public function callback_args(): array {
                        return array( ',', ', ' );
                }

                public function apply_macros( $value, ...$args ): string {
                
                        if ( ! is_string( $value ) ) {
                                return $value;
                        }

                        list( $delimiter_before, $delimiter_after ) = $args;

                        return wp_kses_post( implode( $delimiter_after, explode( $delimiter_before, $value ) ) );
                }
        }

        $filters[] = new Separate_With_Spaces_JFB_Filter();

        return $filters;

} );