Bullshit-Free Engineering

Limit Navigation Sub-Menu Rendering Levels in WordPress

May 29, 2015

The WordPress menu interface is a great way to manipulate navigation menus on your site. If you’re building a theme, however, you may find yourself wanting to limit the number of available sub-menu depths without removing the sub-menu items themselves.

You can style your way around it (styling .sub-menu .sub-menu to act differently than .sub-menu), you can use the wp_nav_menu function’s depth argument to limit the depth, or you can use a custom Walker to force the output to match.

However, if your situation is such that the styling won’t work well and you want to limit navigation sub-menu depth, but not remove any menu items on lower depths (this happens with the depth argument in wp_nav_menu), then the third option is the way to go: create a custom walker.

	<?php
	/**
	* Limit the number of sub-menu levels outputted.
	*
	* Removes the ul wrapper on any sub-menus beyond the 2nd level.
	*
	* @author Joshua David Nelson, josh@joshuadnelson.com
	*/
	// Add menu walker to primary menu
	add_filter( 'wp_nav_menu_args', 'jdn_primary_menu_args' );
	function jdn_primary_menu_args( $args ) {

	if( isset( $args['theme_location'] ) && 'primary' == $args['theme_location'] ) { // change based on the location
	$walker = new JDN_Primary_Nav_Walker;
	$args['walker'] = $walker;
	}

	return $args;

	}

	// Custom Walker
	class JDN_Primary_Nav_Walker extends Walker_Nav_Menu {

	function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
	// Remove 'menu-item-has-children' class from elements beyond the second depth level
	if( $depth > 1 && isset( $item->classes ) && is_array( $item->classes ) && ( $key = array_search( 'menu-item-has-children', $item->classes ) ) !== false ) {
	unset( $item->classes[ $key ] );
	}
	parent::start_el( $output, $item, $depth, $args );
	}

	// Starting of a sub-menu
	function start_lvl( &$output, $depth = 0, $args = array() ) {
	$indent = str_repeat("\t", $depth);
	if( $depth < 2 ) {
	$output .= "\n$indent<ul class='sub-menu'>\n"; // The default wrap
	} elseif( $depth >= 2 ) {
	$output .= "\n$indent\n"; // no sub menu wrap
	}
	}

	// End of a sub-menu
	function end_lvl( &$output, $depth = 0, $args = array() ) {
	$indent = str_repeat("\t", $depth);
	if( $depth < 2 ) {
	$output .= "$indent</ul>\n"; // the default wrap end
	} elseif( $depth >= 2 ) {
	$output .= "\n$indent\n"; // no wrap
	}
	}
	}

view raw limit-sub-menu-level-wp.php hosted with ❤ by GitHub

This removes all sub-menu wraps on sub-menus beyond the second level.

Featured image via Flickr CC, by Basheer Tome

Comments

2 responses to “Limit Navigation Sub-Menu Rendering Levels in WordPress”

krisna

December 23, 2015

can you tell me, how steps to use

thanks

Reply
1. Joshua Nelson
  
  January 5, 2016
  Krisna,
  
  The Walker is called in the jdn_primary_menu_args function. The key thing here is the name of the menu, which is typically theme-specific. In this example 'primary' is the name of the menu location this Walker is applied to in the theme. Change that accordingly for your theme.
  
  For the Walker:
  1. The start_el runs at the start of the list item. This this case, it’s looking at any item with a depth over 1 that has a class menu-item-has-children and removing that class.
  2. The start_lvl is where the sub-menu wrapper ul element is applied. The Walker adds this, like the typical default, but in this case only on any sub-menu with a depth under 2 (so only one level of sub-menus is allowed), otherwise it adds the normal $indent value without the sub-menu wrap.
  3. The end_lvl does something similiar, but it fires at the end and either adds the closing tag or the default $indent value.
  Hope that helps!
  
  Thanks,
  Joshua
  Reply

Limit Navigation Sub-Menu Rendering Levels in WordPress

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2 responses to “Limit Navigation Sub-Menu Rendering Levels in WordPress”

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