CMB2 Dynamic Group Titles

function cmb_group_mod() {
	add_action( is_admin() ? 'admin_footer' : 'wp_footer', 'dynamic_text_to_group_headers' );
}
function dynamic_text_to_group_headers() {
		?>
	
	jQuery( function( $ ) {
		var $box = $( document.getElementById( '_prefix_your_group' ) );
		var replaceTitles = function() {
			$box.find( '.cmb-group-title' ).each( function() {
				var $this = $( this );
				var txt = $this.next().find( '[id$="the_field_to_use"]' ).val();
				var rowindex;
				if ( ! txt ) {
					txt = $box.find( '[data-grouptitle]' ).data( 'grouptitle' );
					if ( txt ) {
						rowindex = $this.parents( '[data-iterator]' ).data( 'iterator' );
						txt = txt.replace( '{#}', ( rowindex + 1 ) );
					}
				}
				if ( txt ) {
					$this.text( txt );
				}
			});
		};
		var replaceOnKeyUp = function( evt ) {
			var $this = $( evt.target );
			var id = 'the_field_to_use';
			if ( evt.target.id.indexOf(id, evt.target.id.length - id.length) !== -1 ) {
				$this.parents( '.cmb-row.cmb-repeatable-grouping' ).find( '.cmb-group-title' ).text( $this.val() );
			}
		};
		$box
			.on( 'cmb2_add_row cmb2_shift_rows_complete', replaceTitles )
			.on( 'keyup', replaceOnKeyUp );
		replaceTitles();
	});
	
<?php }