_wp_menu_output() WordPress Function

function _wp_menu_output( $menu, $submenu, $submenu_as_parent = true ) {
	global $self, $parent_file, $submenu_file, $plugin_page, $typenow;

	$first = true;
	// 0 = menu_title, 1 = capability, 2 = menu_slug, 3 = page_title, 4 = classes, 5 = hookname, 6 = icon_url.
	foreach ( $menu as $key => $item ) {
		$admin_is_parent = false;
		$class           = array();
		$aria_attributes = '';
		$aria_hidden     = '';
		$is_separator    = false;

		if ( $first ) {
			$class[] = 'wp-first-item';
			$first   = false;
		}

		$submenu_items = array();
		if ( ! empty( $submenu[ $item[2] ] ) ) {
			$class[]       = 'wp-has-submenu';
			$submenu_items = $submenu[ $item[2] ];
		}

		if ( ( $parent_file && $item[2] === $parent_file ) || ( empty( $typenow ) && $self === $item[2] ) ) {
			if ( ! empty( $submenu_items ) ) {
				$class[] = 'wp-has-current-submenu wp-menu-open';
			} else {
				$class[]          = 'current';
				$aria_attributes .= 'aria-current="page"';
			}
		} else {
			$class[] = 'wp-not-current-submenu';
			if ( ! empty( $submenu_items ) ) {
				$aria_attributes .= 'aria-haspopup="true"';
			}
		}

		if ( ! empty( $item[4] ) ) {
			$class[] = esc_attr( $item[4] );
		}

		$class     = $class ? ' class="' . implode( ' ', $class ) . '"' : '';
		$id        = ! empty( $item[5] ) ? ' id="' . preg_replace( '|[^a-zA-Z0-9_:.]|', '-', $item[5] ) . '"' : '';
		$img       = '';
		$img_style = '';
		$img_class = ' dashicons-before';

		if ( false !== strpos( $class, 'wp-menu-separator' ) ) {
			$is_separator = true;
		}

		/*
		 * If the string 'none' (previously 'div') is passed instead of a URL, don't output
		 * the default menu image so an icon can be added to div.wp-menu-image as background
		 * with CSS. Dashicons and base64-encoded data:image/svg_xml URIs are also handled
		 * as special cases.
		 */
		if ( ! empty( $item[6] ) ) {
			$img = '<img src="' . esc_url( $item[6] ) . '" alt="" />';

			if ( 'none' === $item[6] || 'div' === $item[6] ) {
				$img = '<br />';
			} elseif ( 0 === strpos( $item[6], 'data:image/svg+xml;base64,' ) ) {
				$img = '<br />';
				// The value is base64-encoded data, so esc_attr() is used here instead of esc_url().
				$img_style = ' style="background-image:url(\'' . esc_attr( $item[6] ) . '\')"';
				$img_class = ' svg';
			} elseif ( 0 === strpos( $item[6], 'dashicons-' ) ) {
				$img       = '<br />';
				$img_class = ' dashicons-before ' . sanitize_html_class( $item[6] );
			}
		}
		$arrow = '<div class="wp-menu-arrow"><div></div></div>';

		$title = wptexturize( $item[0] );

		// Hide separators from screen readers.
		if ( $is_separator ) {
			$aria_hidden = ' aria-hidden="true"';
		}

		echo "\n\t<li$class$id$aria_hidden>";

		if ( $is_separator ) {
			echo '<div class="separator"></div>';
		} elseif ( $submenu_as_parent && ! empty( $submenu_items ) ) {
			$submenu_items = array_values( $submenu_items );  // Re-index.
			$menu_hook     = get_plugin_page_hook( $submenu_items[0][2], $item[2] );
			$menu_file     = $submenu_items[0][2];
			$pos           = strpos( $menu_file, '?' );

			if ( false !== $pos ) {
				$menu_file = substr( $menu_file, 0, $pos );
			}

			if ( ! empty( $menu_hook )
				|| ( ( 'index.php' !== $submenu_items[0][2] )
					&& file_exists( WP_PLUGIN_DIR . "/$menu_file" )
					&& ! file_exists( ABSPATH . "/wp-admin/$menu_file" ) )
			) {
				$admin_is_parent = true;
				echo "<a href='admin.php?page={$submenu_items[0][2]}'$class $aria_attributes>$arrow<div class='wp-menu-image$img_class'$img_style aria-hidden='true'>$img</div><div class='wp-menu-name'>$title</div></a>";
			} else {
				echo "\n\t<a href='{$submenu_items[0][2]}'$class $aria_attributes>$arrow<div class='wp-menu-image$img_class'$img_style aria-hidden='true'>$img</div><div class='wp-menu-name'>$title</div></a>";
			}
		} elseif ( ! empty( $item[2] ) && current_user_can( $item[1] ) ) {
			$menu_hook = get_plugin_page_hook( $item[2], 'admin.php' );
			$menu_file = $item[2];
			$pos       = strpos( $menu_file, '?' );

			if ( false !== $pos ) {
				$menu_file = substr( $menu_file, 0, $pos );
			}

			if ( ! empty( $menu_hook )
				|| ( ( 'index.php' !== $item[2] )
					&& file_exists( WP_PLUGIN_DIR . "/$menu_file" )
					&& ! file_exists( ABSPATH . "/wp-admin/$menu_file" ) )
			) {
				$admin_is_parent = true;
				echo "\n\t<a href='admin.php?page={$item[2]}'$class $aria_attributes>$arrow<div class='wp-menu-image$img_class'$img_style aria-hidden='true'>$img</div><div class='wp-menu-name'>{$item[0]}</div></a>";
			} else {
				echo "\n\t<a href='{$item[2]}'$class $aria_attributes>$arrow<div class='wp-menu-image$img_class'$img_style aria-hidden='true'>$img</div><div class='wp-menu-name'>{$item[0]}</div></a>";
			}
		}

		if ( ! empty( $submenu_items ) ) {
			echo "\n\t<ul class='wp-submenu wp-submenu-wrap'>";
			echo "<li class='wp-submenu-head' aria-hidden='true'>{$item[0]}</li>";

			$first = true;

			// 0 = menu_title, 1 = capability, 2 = menu_slug, 3 = page_title, 4 = classes.
			foreach ( $submenu_items as $sub_key => $sub_item ) {
				if ( ! current_user_can( $sub_item[1] ) ) {
					continue;
				}

				$class           = array();
				$aria_attributes = '';

				if ( $first ) {
					$class[] = 'wp-first-item';
					$first   = false;
				}

				$menu_file = $item[2];
				$pos       = strpos( $menu_file, '?' );

				if ( false !== $pos ) {
					$menu_file = substr( $menu_file, 0, $pos );
				}

				// Handle current for post_type=post|page|foo pages, which won't match $self.
				$self_type = ! empty( $typenow ) ? $self . '?post_type=' . $typenow : 'nothing';

				if ( isset( $submenu_file ) ) {
					if ( $submenu_file === $sub_item[2] ) {
						$class[]          = 'current';
						$aria_attributes .= ' aria-current="page"';
					}
					// If plugin_page is set the parent must either match the current page or not physically exist.
					// This allows plugin pages with the same hook to exist under different parents.
				} elseif (
					( ! isset( $plugin_page ) && $self === $sub_item[2] )
					|| ( isset( $plugin_page ) && $plugin_page === $sub_item[2]
						&& ( $item[2] === $self_type || $item[2] === $self || file_exists( $menu_file ) === false ) )
				) {
					$class[]          = 'current';
					$aria_attributes .= ' aria-current="page"';
				}

				if ( ! empty( $sub_item[4] ) ) {
					$class[] = esc_attr( $sub_item[4] );
				}

				$class = $class ? ' class="' . implode( ' ', $class ) . '"' : '';

				$menu_hook = get_plugin_page_hook( $sub_item[2], $item[2] );
				$sub_file  = $sub_item[2];
				$pos       = strpos( $sub_file, '?' );
				if ( false !== $pos ) {
					$sub_file = substr( $sub_file, 0, $pos );
				}

				$title = wptexturize( $sub_item[0] );

				if ( ! empty( $menu_hook )
					|| ( ( 'index.php' !== $sub_item[2] )
						&& file_exists( WP_PLUGIN_DIR . "/$sub_file" )
						&& ! file_exists( ABSPATH . "/wp-admin/$sub_file" ) )
				) {
					// If admin.php is the current page or if the parent exists as a file in the plugins or admin directory.
					if ( ( ! $admin_is_parent && file_exists( WP_PLUGIN_DIR . "/$menu_file" ) && ! is_dir( WP_PLUGIN_DIR . "/{$item[2]}" ) ) || file_exists( $menu_file ) ) {
						$sub_item_url = add_query_arg( array( 'page' => $sub_item[2] ), $item[2] );
					} else {
						$sub_item_url = add_query_arg( array( 'page' => $sub_item[2] ), 'admin.php' );
					}

					$sub_item_url = esc_url( $sub_item_url );
					echo "<li$class><a href='$sub_item_url'$class$aria_attributes>$title</a></li>";
				} else {
					echo "<li$class><a href='{$sub_item[2]}'$class$aria_attributes>$title</a></li>";
				}
			}
			echo '</ul>';
		}
		echo '</li>';
	}

	echo '<li id="collapse-menu" class="hide-if-no-js">' .
		'<button type="button" id="collapse-button" aria-label="' . esc_attr__( 'Collapse Main menu' ) . '" aria-expanded="true">' .
		'<span class="collapse-button-icon" aria-hidden="true"></span>' .
		'<span class="collapse-button-label">' . __( 'Collapse menu' ) . '</span>' .
		'</button></li>';
}