Voxel Mods: Trim Post Content by Heading Range

Examples:

Display content from the beginning of the post to the 1st heading

• Start Heading: 0
• End Heading: 1
• This will display everything from the start of the post, including any elements like images, paragraphs, or blocks, up to and including the 1st heading and will include any non-heading HTML content that follows.

Display content grouped under the 2nd heading

• Start Heading: 2
• End Heading: 2
• This will display all content from the 2nd heading and will include any non-heading content (images, paragraphs, or other blocks) that follows, up to the next heading’s start (up to heading 3 in this case).

Display content from the 3rd heading to the 4th heading

• Start Heading: 3
• End Heading: 4
• This will display all content starting from the 3rd heading up until and including the 4th heading block and will include any content (images, paragraphs, or other blocks that follow up to heading 5).

Display content starting from the 5th heading to the end of the post

• Start Heading: 5
• End Heading: (leave blank)
• This will display everything starting from the 5th heading block and continuing until the end of the post, including all other elements like paragraphs, images, and buttons.

Conclusion:

This modifier gives you precise control over which sections of a post to display, and which sections to add a section break so you can insert your templated content within the post data.

The Code: Voxel Theme Modifier: Trim Post by Heading Range

*** Disclaimer – Use at your own risk. Always make a backup. ***

Add to your child theme’s functions.php file.

add_filter( 'voxel/dynamic-data/modifiers', function( $modifiers ) {
    class Trim_Post_By_Heading_Range extends \Voxel\Dynamic_Data\Modifiers\Base_Modifier {
        public function get_label(): string {
            return 'Trim Post by Heading Range';
        }

        public function get_key(): string {
            return 'trim_post_by_heading_range';
        }

        protected function define_args(): void {
            $this->define_arg( [
                'type' => 'text',
                'label' => _x( 'Start Heading (0 for start)', 'modifiers', 'voxel-backend' ),
            ] );

            $this->define_arg( [
                'type' => 'text',
                'label' => _x( 'End Heading (leave blank for end)', 'modifiers', 'voxel-backend' ),
            ] );
        }

        public function apply( string $value ) {
            // Ensure we're working with the post content (get_the_content())
            $post_content = get_the_content();

            // If the content is empty or not available, return an empty string
            if ( empty( $post_content ) ) {
                return '';
            }

            // Parse the blocks from the post content
            $blocks = parse_blocks( $post_content );

            // Get the start and end heading indices
            $start_heading = absint( $this->get_arg(0) ?: 0 );
            $end_heading = $this->get_arg(1) !== '' ? absint( $this->get_arg(1) ) : PHP_INT_MAX;

            $current_heading_count = 0;
            $trimmed_blocks = [];

            foreach ( $blocks as $block ) {
                // Check if the block is a heading (core, GenerateBlocks, or Kadence Blocks)
                if ( 
                    $block['blockName'] === 'core/heading' || 
                    $block['blockName'] === 'generateblocks/headline' || 
                    $block['blockName'] === 'kadence/advancedheading' 
                ) {
                    $current_heading_count++;
                }

                // Respect the start heading even if end heading is blank
                if ( $current_heading_count >= $start_heading && $current_heading_count <= $end_heading ) {
                    $trimmed_blocks[] = $block;
                }

                // Stop processing if we've passed the end range
                if ( $current_heading_count > $end_heading ) {
                    break;
                }
            }

            // Rebuild content from the selected blocks
            $output = '';
            foreach ( $trimmed_blocks as $block ) {
                // Render block content using WordPress filters
                $output .= apply_filters( 'the_content', render_block( $block ) );
            }

            // Escape the output to prevent XSS but allow valid HTML content
            return wp_kses_post( $output );
        }
    }

    $modifiers['trim_post_by_heading_range'] = \Trim_Post_By_Heading_Range::class;
    return $modifiers;
} );

To implement this solution, you’ll need to add the code to your WordPress site. You have two options for where to place this code:

• Child Theme’s functions.php File:

  If you’re already using a child theme (recommended for customization), simply add the PHP code to your functions.php file. This will ensure your changes are preserved even if the main Voxel theme is updated.

• Code Snippets Plugin:

  If you prefer not to edit theme files directly, or if you want to manage your custom code more easily, you can use the Fluent Snippets plugin. This plugin allows you to add custom PHP code without touching your theme files. Just create a new function.php snippet, paste the code, and activate it.

Then apply this Voxel Mod from the Elementor builder interface.