_content/js/site.js - website - Git at Google

 // Copyright 2019 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 /**
  * A bit of navigation related code for handling dismissible elements.
  */
 window.initFuncs = [];

 (() => {
   'use strict';

   function registerHeaderListeners() {
     // Desktop menu hover state
     const menuItemHovers = document.querySelectorAll('.js-desktop-menu-hover');
     menuItemHovers.forEach(menuItemHover => {
       // when user clicks on the dropdown menu item on desktop or mobile,
       // force the menu to stay open until the user clicks off of it.
       menuItemHover.addEventListener('mouseenter', e => {
         const forced = document.querySelector('.forced-open');
         if (forced && forced !== menuItemHover) {
           forced.blur();
           forced.classList.remove('forced-open');
         }
         // prevents menus that have been tabbed into from staying open
         // when you hover over another menu
         e.target.classList.remove('forced-closed');
         e.target.classList.add('forced-open');
       });
       const toggleForcedOpen = e => {
         const isForced = e.target.classList.contains('forced-open');
         const target = e.currentTarget;
         if (isForced) {
           target.removeEventListener('blur', e =>
             target.classList.remove('forced-open')
           );
           target.classList.remove('forced-open');
           target.classList.add('forced-closed');
           target.blur();
           target.parentNode.addEventListener('mouseout', () => {
             target.classList.remove('forced-closed');
           });
         } else {
           target.classList.remove('forced-closed');
           target.classList.add('forced-open');
           target.parentNode.removeEventListener('mouseout', () => {
             target.classList.remove('forced-closed');
           });
         }
         e.target.focus();
       };
       menuItemHover.addEventListener('click', toggleForcedOpen);
       menuItemHover.addEventListener('focus', e => {
         e.target.classList.add('forced-closed');
         e.target.classList.remove('forced-open');
       });

       // ensure focus is removed when esc is pressed
       const focusOutOnEsc = e => {
         if (e.key === 'Escape') {
           const textarea = document.getElementById('code');
           if (e.target == textarea) {
             e.preventDefault();
             textarea.blur();
           }
           else {
             const forcedOpenItem = document.querySelector('.forced-open');
             const target = e.currentTarget;
             if (forcedOpenItem) {
               forcedOpenItem.classList.remove('forced-open');
               forcedOpenItem.blur();
               forcedOpenItem.classList.add('forced-closed');
               e.target.focus();
             }
           }
         }
       };
       document.addEventListener('keydown', focusOutOnEsc);
     });

     // Mobile menu subnav menus
     const header = document.querySelector('.js-header');
     const headerbuttons = document.querySelectorAll('.js-headerMenuButton');
     headerbuttons.forEach(button => {
       button.addEventListener('click', e => {
         e.preventDefault();
         const isActive = header.classList.contains('is-active');
         if (isActive) {
           handleNavigationDrawerInactive(header);
         } else {
           handleNavigationDrawerActive(header);
         }
         button.setAttribute('aria-expanded', isActive);
       });
     });

     const scrim = document.querySelector('.js-scrim');
     scrim.addEventListener('click', e => {
       e.preventDefault();

       // find any active submenus and close them
       const activeSubnavs = document.querySelectorAll(
         '.NavigationDrawer-submenuItem.is-active'
       );
       activeSubnavs.forEach(subnav => handleNavigationDrawerInactive(subnav));

       handleNavigationDrawerInactive(header);

       headerbuttons.forEach(button => {
         button.setAttribute(
           'aria-expanded',
           header.classList.contains('is-active')
         );
       });
     });

     const getNavigationDrawerMenuItems = navigationDrawer => [
       navigationDrawer.querySelector('.NavigationDrawer-header > a'),
       ...navigationDrawer.querySelectorAll(
         ':scope > .NavigationDrawer-nav > .NavigationDrawer-list > .NavigationDrawer-listItem > a, :scope > .NavigationDrawer-nav > .NavigationDrawer-list > .NavigationDrawer-listItem > .Header-socialIcons > a'
       ),
     ];

     const getNavigationDrawerIsSubnav = navigationDrawer =>
       navigationDrawer.classList.contains('NavigationDrawer-submenuItem');

     const handleNavigationDrawerInactive = navigationDrawer => {
       const menuItems = getNavigationDrawerMenuItems(navigationDrawer);
       navigationDrawer.classList.remove('is-active');
       const parentMenuItem = navigationDrawer
         .closest('.NavigationDrawer-listItem')
         ?.querySelector(':scope > a');
       parentMenuItem?.focus();

       menuItems.forEach(item => item.setAttribute('tabindex', '-1'));

       menuItems[0].removeEventListener(
         'keydown',
         handleMenuItemTabLeft.bind(navigationDrawer)
       );
       menuItems[menuItems.length - 1].removeEventListener(
         'keydown',
         handleMenuItemTabRight.bind(navigationDrawer)
       );

       if (navigationDrawer === header) {
         headerbuttons[0]?.focus();
       }
     };

     const handleNavigationDrawerActive = navigationDrawer => {
       const menuItems = getNavigationDrawerMenuItems(navigationDrawer);

       navigationDrawer.classList.add('is-active');
       menuItems.forEach(item => item.setAttribute('tabindex', '0'));
       menuItems[0].focus();

       menuItems[0].addEventListener(
         'keydown',
         handleMenuItemTabLeft.bind(this, navigationDrawer)
       );
       menuItems[menuItems.length - 1].addEventListener(
         'keydown',
         handleMenuItemTabRight.bind(this, navigationDrawer)
       );
     };

     const handleMenuItemTabLeft = (navigationDrawer, e) => {
       if (e.key === 'Tab' && e.shiftKey) {
         e.preventDefault();
         handleNavigationDrawerInactive(navigationDrawer);
       }
     };

     const handleMenuItemTabRight = (navigationDrawer, e) => {
       if (e.key === 'Tab' && !e.shiftKey) {
         e.preventDefault();
         handleNavigationDrawerInactive(navigationDrawer);
       }
     };

     const prepMobileNavigationDrawer = navigationDrawer => {
       const isSubnav = getNavigationDrawerIsSubnav(navigationDrawer);
       const menuItems = getNavigationDrawerMenuItems(navigationDrawer);

       navigationDrawer.addEventListener('keyup', e => {
         if (e.key === 'Escape') {
           handleNavigationDrawerInactive(navigationDrawer);
         }
       });

       menuItems.forEach(item => {
         const parentLi = item.closest('li');
         if (
           parentLi &&
           parentLi.classList.contains('js-mobile-subnav-trigger')
         ) {
           const submenu = parentLi.querySelector(
             '.NavigationDrawer-submenuItem'
           );
           item.addEventListener('click', () => {
             handleNavigationDrawerActive(submenu);
           });
         }
       });
       if (isSubnav) {
         handleNavigationDrawerInactive(navigationDrawer);
         navigationDrawer
           .querySelector('.NavigationDrawer-header')
           .addEventListener('click', e => {
             e.preventDefault();
             handleNavigationDrawerInactive(navigationDrawer);
           });
       }
     };

     document
       .querySelectorAll('.NavigationDrawer')
       .forEach(drawer => prepMobileNavigationDrawer(drawer));
     handleNavigationDrawerInactive(header);
   }

   /**
    * Attempts to detect user's operating system and sets the download
    * links accordingly
    */
   async function setDownloadLinks() {
     const versionElement = document.querySelector('.js-latestGoVersion');
     if (versionElement) {
       const anchorTagWindows = document.querySelector('.js-downloadWin');
       const anchorTagMac = document.querySelector('.js-downloadMac');
       const anchorTagLinux = document.querySelector('.js-downloadLinux');
       const version = await getLatestVersion();

       const macDownloadUrl = `/dl/${version}.darwin-amd64.pkg`;
       const windowsDownloadUrl = `/dl/${version}.windows-amd64.msi`;
       const linuxDownloadUrl = `/dl/${version}.linux-amd64.tar.gz`;

       anchorTagWindows.href = windowsDownloadUrl;
       anchorTagMac.href = macDownloadUrl;
       anchorTagLinux.href = linuxDownloadUrl;

       /*
        * Note: we do not change .js-downloadBtn anymore
        * because it is impossible to tell reliably which architecture
        * the user's browser is running on.
        */
     }
   }

   function registerPortToggles() {
     for (const el of document.querySelectorAll('.js-togglePorts')) {
       el.addEventListener('click', () => {
         el.setAttribute('aria-expanded', el.getAttribute('aria-expanded') === 'true' ? 'false' : 'true')
       })
     }
   }

   /**
    * Retrieves list of Go versions & returns the latest
    */
   async function getLatestVersion() {
     let version = 'go1.17'; // fallback version if fetch fails
     try {
       const versionData = await (await fetch('/dl/?mode=json')).json();
       if (!versionData.length) {
         return version;
       }
       versionData.sort((v1, v2) => {
         return v2.version - v1.version;
       });
       version = versionData[0].version;
     } catch (err) {
       console.error(err);
     }
     return version;
   }

   /**
    * initialThemeSetup sets data-theme attribute based on preferred color
    */

   function initialThemeSetup() {
     const themeCookie = document.cookie.match(
       /prefers-color-scheme=(light|dark|auto)/
     );
     const theme = themeCookie && themeCookie.length > 0 && themeCookie[1];
     if (theme) {
       document.querySelector('html').setAttribute('data-theme', theme);
     }
   }

   /**
    * setThemeButtons sets click listeners for toggling theme buttons
    */
   function setThemeButtons() {
     for (const el of document.querySelectorAll('.js-toggleTheme')) {
       el.addEventListener('click', () => {
         toggleTheme();
       });
     }
   }

   /**
    * setVersionSpan sets the latest version in any span that has this selector.
    */
   async function setVersionSpans() {
     const spans = document.querySelectorAll('.GoVersionSpan');
     if (!spans) return;
     const version = await getLatestVersion();
     Array.from(spans).forEach(span => {
       span.textContent = `Download (${version.replace('go', '')})`
     });
   }

   /**
    * toggleTheme switches the preferred color scheme between auto, light, and dark.
    */
   function toggleTheme() {
     let nextTheme = 'dark';
     const theme = document.documentElement.getAttribute('data-theme');
     if (theme === 'dark') {
       nextTheme = 'light';
     } else if (theme === 'light') {
       nextTheme = 'auto';
     }
     let domain = '';
     if (location.hostname === 'go.dev') {
       // Include subdomains to apply the setting to pkg.go.dev.
       domain = 'domain=.go.dev;';
     }
     document.documentElement.setAttribute('data-theme', nextTheme);
     document.cookie = `prefers-color-scheme=${nextTheme};${domain}path=/;max-age=31536000;`;
   }

   function registerCookieNotice() {
     const themeCookie = document.cookie.match(/cookie-consent=true/);
     if (!themeCookie) {
       const notice = document.querySelector('.js-cookieNotice');
       const button = notice.querySelector('button');
       notice.classList.add('Cookie-notice--visible');
       button.addEventListener('click', () => {
         let domain = '';
         if (location.hostname === 'go.dev') {
           // Apply the cookie to *.go.dev.
           domain = 'domain=.go.dev;';
         }
         document.cookie = `cookie-consent=true;${domain}path=/;max-age=31536000`;
         notice.remove();
       });
     }
   }

   initialThemeSetup();

   const onPageLoad = () => {
     registerHeaderListeners();
     setDownloadLinks();
     setThemeButtons();
     setVersionSpans();
     registerPortToggles();
     registerCookieNotice();
   };

   // DOM might be already loaded when we try to setup the callback, hence the check.
   if (document.readyState !== 'loading') {
     onPageLoad();
   } else {
     document.addEventListener('DOMContentLoaded', onPageLoad);
   }
 })();
	// Copyright 2019 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	/**
	* A bit of navigation related code for handling dismissible elements.
	*/
	window.initFuncs = [];

	(() => {
	'use strict';

	function registerHeaderListeners() {
	// Desktop menu hover state
	const menuItemHovers = document.querySelectorAll('.js-desktop-menu-hover');
	menuItemHovers.forEach(menuItemHover => {
	// when user clicks on the dropdown menu item on desktop or mobile,
	// force the menu to stay open until the user clicks off of it.
	menuItemHover.addEventListener('mouseenter', e => {
	const forced = document.querySelector('.forced-open');
	if (forced && forced !== menuItemHover) {
	forced.blur();
	forced.classList.remove('forced-open');
	}
	// prevents menus that have been tabbed into from staying open
	// when you hover over another menu
	e.target.classList.remove('forced-closed');
	e.target.classList.add('forced-open');
	});
	const toggleForcedOpen = e => {
	const isForced = e.target.classList.contains('forced-open');
	const target = e.currentTarget;
	if (isForced) {
	target.removeEventListener('blur', e =>
	target.classList.remove('forced-open')
	);
	target.classList.remove('forced-open');
	target.classList.add('forced-closed');
	target.blur();
	target.parentNode.addEventListener('mouseout', () => {
	target.classList.remove('forced-closed');
	});
	} else {
	target.classList.remove('forced-closed');
	target.classList.add('forced-open');
	target.parentNode.removeEventListener('mouseout', () => {
	target.classList.remove('forced-closed');
	});
	}
	e.target.focus();
	};
	menuItemHover.addEventListener('click', toggleForcedOpen);
	menuItemHover.addEventListener('focus', e => {
	e.target.classList.add('forced-closed');
	e.target.classList.remove('forced-open');
	});

	// ensure focus is removed when esc is pressed
	const focusOutOnEsc = e => {
	if (e.key === 'Escape') {
	const textarea = document.getElementById('code');
	if (e.target == textarea) {
	e.preventDefault();
	textarea.blur();
	}
	else {
	const forcedOpenItem = document.querySelector('.forced-open');
	const target = e.currentTarget;
	if (forcedOpenItem) {
	forcedOpenItem.classList.remove('forced-open');
	forcedOpenItem.blur();
	forcedOpenItem.classList.add('forced-closed');
	e.target.focus();
	}
	}
	}
	};
	document.addEventListener('keydown', focusOutOnEsc);
	});

	// Mobile menu subnav menus
	const header = document.querySelector('.js-header');
	const headerbuttons = document.querySelectorAll('.js-headerMenuButton');
	headerbuttons.forEach(button => {
	button.addEventListener('click', e => {
	e.preventDefault();
	const isActive = header.classList.contains('is-active');
	if (isActive) {
	handleNavigationDrawerInactive(header);
	} else {
	handleNavigationDrawerActive(header);
	}
	button.setAttribute('aria-expanded', isActive);
	});
	});

	const scrim = document.querySelector('.js-scrim');
	scrim.addEventListener('click', e => {
	e.preventDefault();

	// find any active submenus and close them
	const activeSubnavs = document.querySelectorAll(
	'.NavigationDrawer-submenuItem.is-active'
	);
	activeSubnavs.forEach(subnav => handleNavigationDrawerInactive(subnav));

	handleNavigationDrawerInactive(header);

	headerbuttons.forEach(button => {
	button.setAttribute(
	'aria-expanded',
	header.classList.contains('is-active')
	);
	});
	});

	const getNavigationDrawerMenuItems = navigationDrawer => [
	navigationDrawer.querySelector('.NavigationDrawer-header > a'),
	...navigationDrawer.querySelectorAll(
	':scope > .NavigationDrawer-nav > .NavigationDrawer-list > .NavigationDrawer-listItem > a, :scope > .NavigationDrawer-nav > .NavigationDrawer-list > .NavigationDrawer-listItem > .Header-socialIcons > a'
	),
	];

	const getNavigationDrawerIsSubnav = navigationDrawer =>
	navigationDrawer.classList.contains('NavigationDrawer-submenuItem');

	const handleNavigationDrawerInactive = navigationDrawer => {
	const menuItems = getNavigationDrawerMenuItems(navigationDrawer);
	navigationDrawer.classList.remove('is-active');
	const parentMenuItem = navigationDrawer
	.closest('.NavigationDrawer-listItem')
	?.querySelector(':scope > a');
	parentMenuItem?.focus();

	menuItems.forEach(item => item.setAttribute('tabindex', '-1'));

	menuItems[0].removeEventListener(
	'keydown',
	handleMenuItemTabLeft.bind(navigationDrawer)
	);
	menuItems[menuItems.length - 1].removeEventListener(
	'keydown',
	handleMenuItemTabRight.bind(navigationDrawer)
	);

	if (navigationDrawer === header) {
	headerbuttons[0]?.focus();
	}
	};

	const handleNavigationDrawerActive = navigationDrawer => {
	const menuItems = getNavigationDrawerMenuItems(navigationDrawer);

	navigationDrawer.classList.add('is-active');
	menuItems.forEach(item => item.setAttribute('tabindex', '0'));
	menuItems[0].focus();

	menuItems[0].addEventListener(
	'keydown',
	handleMenuItemTabLeft.bind(this, navigationDrawer)
	);
	menuItems[menuItems.length - 1].addEventListener(
	'keydown',
	handleMenuItemTabRight.bind(this, navigationDrawer)
	);
	};

	const handleMenuItemTabLeft = (navigationDrawer, e) => {
	if (e.key === 'Tab' && e.shiftKey) {
	e.preventDefault();
	handleNavigationDrawerInactive(navigationDrawer);
	}
	};

	const handleMenuItemTabRight = (navigationDrawer, e) => {
	if (e.key === 'Tab' && !e.shiftKey) {
	e.preventDefault();
	handleNavigationDrawerInactive(navigationDrawer);
	}
	};

	const prepMobileNavigationDrawer = navigationDrawer => {
	const isSubnav = getNavigationDrawerIsSubnav(navigationDrawer);
	const menuItems = getNavigationDrawerMenuItems(navigationDrawer);

	navigationDrawer.addEventListener('keyup', e => {
	if (e.key === 'Escape') {
	handleNavigationDrawerInactive(navigationDrawer);
	}
	});

	menuItems.forEach(item => {
	const parentLi = item.closest('li');
	if (
	parentLi &&
	parentLi.classList.contains('js-mobile-subnav-trigger')
	) {
	const submenu = parentLi.querySelector(
	'.NavigationDrawer-submenuItem'
	);
	item.addEventListener('click', () => {
	handleNavigationDrawerActive(submenu);
	});
	}
	});
	if (isSubnav) {
	handleNavigationDrawerInactive(navigationDrawer);
	navigationDrawer
	.querySelector('.NavigationDrawer-header')
	.addEventListener('click', e => {
	e.preventDefault();
	handleNavigationDrawerInactive(navigationDrawer);
	});
	}
	};

	document
	.querySelectorAll('.NavigationDrawer')
	.forEach(drawer => prepMobileNavigationDrawer(drawer));
	handleNavigationDrawerInactive(header);
	}

	/**
	* Attempts to detect user's operating system and sets the download
	* links accordingly
	*/
	async function setDownloadLinks() {
	const versionElement = document.querySelector('.js-latestGoVersion');
	if (versionElement) {
	const anchorTagWindows = document.querySelector('.js-downloadWin');
	const anchorTagMac = document.querySelector('.js-downloadMac');
	const anchorTagLinux = document.querySelector('.js-downloadLinux');
	const version = await getLatestVersion();

	const macDownloadUrl = `/dl/${version}.darwin-amd64.pkg`;
	const windowsDownloadUrl = `/dl/${version}.windows-amd64.msi`;
	const linuxDownloadUrl = `/dl/${version}.linux-amd64.tar.gz`;

	anchorTagWindows.href = windowsDownloadUrl;
	anchorTagMac.href = macDownloadUrl;
	anchorTagLinux.href = linuxDownloadUrl;

	/*
	* Note: we do not change .js-downloadBtn anymore
	* because it is impossible to tell reliably which architecture
	* the user's browser is running on.
	*/
	}
	}

	function registerPortToggles() {
	for (const el of document.querySelectorAll('.js-togglePorts')) {
	el.addEventListener('click', () => {
	el.setAttribute('aria-expanded', el.getAttribute('aria-expanded') === 'true' ? 'false' : 'true')
	})
	}
	}

	/**
	* Retrieves list of Go versions & returns the latest
	*/
	async function getLatestVersion() {
	let version = 'go1.17'; // fallback version if fetch fails
	try {
	const versionData = await (await fetch('/dl/?mode=json')).json();
	if (!versionData.length) {
	return version;
	}
	versionData.sort((v1, v2) => {
	return v2.version - v1.version;
	});
	version = versionData[0].version;
	} catch (err) {
	console.error(err);
	}
	return version;
	}

	/**
	* initialThemeSetup sets data-theme attribute based on preferred color
	*/

	function initialThemeSetup() {
	const themeCookie = document.cookie.match(
	/prefers-color-scheme=(light\|dark\|auto)/
	);
	const theme = themeCookie && themeCookie.length > 0 && themeCookie[1];
	if (theme) {
	document.querySelector('html').setAttribute('data-theme', theme);
	}
	}

	/**
	* setThemeButtons sets click listeners for toggling theme buttons
	*/
	function setThemeButtons() {
	for (const el of document.querySelectorAll('.js-toggleTheme')) {
	el.addEventListener('click', () => {
	toggleTheme();
	});
	}
	}

	/**
	* setVersionSpan sets the latest version in any span that has this selector.
	*/
	async function setVersionSpans() {
	const spans = document.querySelectorAll('.GoVersionSpan');
	if (!spans) return;
	const version = await getLatestVersion();
	Array.from(spans).forEach(span => {
	span.textContent = `Download (${version.replace('go', '')})`
	});
	}

	/**
	* toggleTheme switches the preferred color scheme between auto, light, and dark.
	*/
	function toggleTheme() {
	let nextTheme = 'dark';
	const theme = document.documentElement.getAttribute('data-theme');
	if (theme === 'dark') {
	nextTheme = 'light';
	} else if (theme === 'light') {
	nextTheme = 'auto';
	}
	let domain = '';
	if (location.hostname === 'go.dev') {
	// Include subdomains to apply the setting to pkg.go.dev.
	domain = 'domain=.go.dev;';
	}
	document.documentElement.setAttribute('data-theme', nextTheme);
	document.cookie = `prefers-color-scheme=${nextTheme};${domain}path=/;max-age=31536000;`;
	}

	function registerCookieNotice() {
	const themeCookie = document.cookie.match(/cookie-consent=true/);
	if (!themeCookie) {
	const notice = document.querySelector('.js-cookieNotice');
	const button = notice.querySelector('button');
	notice.classList.add('Cookie-notice--visible');
	button.addEventListener('click', () => {
	let domain = '';
	if (location.hostname === 'go.dev') {
	// Apply the cookie to *.go.dev.
	domain = 'domain=.go.dev;';
	}
	document.cookie = `cookie-consent=true;${domain}path=/;max-age=31536000`;
	notice.remove();
	});
	}
	}

	initialThemeSetup();

	const onPageLoad = () => {
	registerHeaderListeners();
	setDownloadLinks();
	setThemeButtons();
	setVersionSpans();
	registerPortToggles();
	registerCookieNotice();
	};

	// DOM might be already loaded when we try to setup the callback, hence the check.
	if (document.readyState !== 'loading') {
	onPageLoad();
	} else {
	document.addEventListener('DOMContentLoaded', onPageLoad);
	}
	})();