143 lines
4.2 KiB
JavaScript
143 lines
4.2 KiB
JavaScript
/**
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* File navigation.js.
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*
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* Handles toggling the navigation menu for small screens and enables TAB key
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* navigation support for dropdown menus.
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*/
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( function() {
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const siteNavigation = document.getElementById( 'site-navigation' );
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// Return early if the navigation doesn't exist.
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if ( ! siteNavigation ) {
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return;
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}
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const button = siteNavigation.getElementsByTagName( 'button' )[ 0 ];
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// Return early if the button doesn't exist.
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if ( 'undefined' === typeof button ) {
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return;
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}
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const menu = siteNavigation.getElementsByTagName( 'ul' )[ 0 ];
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// Hide menu toggle button if menu is empty and return early.
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if ( 'undefined' === typeof menu ) {
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button.style.display = 'none';
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return;
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}
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if ( ! menu.classList.contains( 'nav-menu' ) ) {
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menu.classList.add( 'nav-menu' );
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}
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// Toggle the .toggled class and the aria-expanded value each time the button is clicked.
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button.addEventListener( 'click', function() {
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siteNavigation.classList.toggle( 'toggled' );
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let menuContainer = siteNavigation.querySelector('.menu-menu-container');
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if (menuContainer) {
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slideToggle(menuContainer, 300);
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}
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if ( button.getAttribute( 'aria-expanded' ) === 'true' ) {
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button.setAttribute( 'aria-expanded', 'false' );
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} else {
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button.setAttribute( 'aria-expanded', 'true' );
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}
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} );
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// Remove the .toggled class and set aria-expanded to false when the user clicks outside the navigation.
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document.addEventListener( 'click', function( event ) {
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const isClickInside = siteNavigation.contains( event.target );
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if ( ! isClickInside ) {
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siteNavigation.classList.remove( 'toggled' );
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button.setAttribute( 'aria-expanded', 'false' );
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}
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} );
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// Get all the link elements within the menu.
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const links = menu.getElementsByTagName( 'a' );
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// Get all the link elements with children within the menu.
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const linksWithChildren = menu.querySelectorAll( '.menu-item-has-children > a, .page_item_has_children > a' );
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// Toggle focus each time a menu link is focused or blurred.
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for ( const link of links ) {
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link.addEventListener( 'focus', toggleFocus, true );
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link.addEventListener( 'blur', toggleFocus, true );
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}
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// Toggle focus each time a menu link with children receive a touch event.
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for ( const link of linksWithChildren ) {
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link.addEventListener( 'touchstart', toggleFocus, false );
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}
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/**
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* Sets or removes .focus class on an element.
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*/
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function toggleFocus() {
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if ( event.type === 'focus' || event.type === 'blur' ) {
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let self = this;
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// Move up through the ancestors of the current link until we hit .nav-menu.
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while ( ! self.classList.contains( 'nav-menu' ) ) {
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// On li elements toggle the class .focus.
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if ( 'li' === self.tagName.toLowerCase() ) {
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self.classList.toggle( 'focus' );
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}
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self = self.parentNode;
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}
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}
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if ( event.type === 'touchstart' ) {
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const menuItem = this.parentNode;
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event.preventDefault();
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for ( const link of menuItem.parentNode.children ) {
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if ( menuItem !== link ) {
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link.classList.remove( 'focus' );
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}
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}
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menuItem.classList.toggle( 'focus' );
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}
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}
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function slideToggle(element, duration = 300) {
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if (window.getComputedStyle(element).display === 'none') {
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// slideDown
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element.style.removeProperty('display');
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let display = window.getComputedStyle(element).display;
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if (display === 'none') display = 'block';
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element.style.display = display;
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let height = element.offsetHeight;
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element.style.overflow = 'hidden';
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element.style.height = '0px';
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element.offsetHeight; // force reflow
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element.style.transition = `height ${duration}ms ease`;
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element.style.height = height + 'px';
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setTimeout(() => {
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element.style.removeProperty('height');
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element.style.removeProperty('overflow');
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element.style.removeProperty('transition');
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}, duration);
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} else {
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// slideUp
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element.style.height = element.offsetHeight + 'px';
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element.offsetHeight; // force reflow
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element.style.transition = `height ${duration}ms ease`;
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element.style.height = '0px';
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element.style.overflow = 'hidden';
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setTimeout(() => {
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element.style.display = 'none';
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element.style.removeProperty('height');
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element.style.removeProperty('overflow');
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element.style.removeProperty('transition');
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}, duration);
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}
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}
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}() );
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