Add Font Awesome icons to WordPress menu anchor text

wp-fa-menu-anchor-icons.php

<?php //* Mind this opening PHP tag

/**
 *	Append Font Awesome icons to menu-item anchor text
 *	Requires the "fa" and "fa-{icon_key}" classes to be added to the menu item
 *
 *	@author Ren Ventura <EngageWP.com>
 *	@link http://www.engagewp.com/add-font-awesome-icons-to-wordpress-menu-anchor-text/
 *
 *	@param $item Menu-item object
 *	@return $item Modified menu-item object
 */
add_filter( 'wp_setup_nav_menu_item', 'rv_wp_setup_nav_menu_item' );
function rv_wp_setup_nav_menu_item( $item ) {

	// If not in the admin and 'fa' is an included class
	if ( ! is_admin() && in_array( 'fa', $item->classes ) ) {

		// Create an array for the Font Awesome classes
		$font_awesome_classes = array( 'fa' );

		foreach( $item->classes as $key => $class ) {

			// Start removing the F.A. classes from the parent li tag, otherwise icons display twice
			if ( $class === 'fa' )
				unset( $item->classes[$key] );

			// If the class is a font-awesome icon
			if ( substr( $class, 0, 3 ) === 'fa-' ) {

				// Throw the icon class into the array
				$font_awesome_classes[] = $class;

				// Finish removing the F.A. classes from parent li
				unset( $item->classes[$key] );

				// Use only one icon if multiple icons are present
				break;
			}
		}

		// Create the icon markup
		$icon_tag = sprintf( '<span class="link-icon"><i class="%s"></i></span>', implode( ' ', $font_awesome_classes ) );

		// Prepend the icon markup to the anchor text
		$item->title = $icon_tag . $item->title;
	}

	return $item;
}