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1 // Copyright 2013 The Chromium Authors. All rights reserved. | 1 // Copyright 2013 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 // Scroll handling. | 5 // Scroll handling. |
6 // | 6 // |
7 // Switches the sidebar between floating on the left and position:fixed | 7 // Switches the sidebar between floating on the left and position:fixed |
8 // depending on whether it's scrolled into view, and manages the scroll-to-top | 8 // depending on whether it's scrolled into view, and manages the scroll-to-top |
9 // button: click logic, and when to show it. | 9 // button: click logic, and when to show it. |
10 (function() { | 10 (function() { |
11 | 11 |
12 var isLargerThanMobileQuery = | 12 var isLargerThanMobileQuery = |
13 window.matchMedia('screen and (min-width: 581px)'); | 13 window.matchMedia('screen and (min-width: 581px)'); |
14 | 14 |
15 var sidebar = document.querySelector('.inline-toc'); | 15 var sidebar = document.querySelector('.inline-toc'); |
16 var sidebarOffsetTop = null; | |
17 var articleBody = document.querySelector('[itemprop="articleBody"]'); | 16 var articleBody = document.querySelector('[itemprop="articleBody"]'); |
18 | 17 |
19 // Bomb out unless we're on an article page and have a TOC. | 18 // Bomb out unless we're on an article page and have a TOC. |
20 if (!(sidebar && articleBody)) { | 19 if (!(sidebar && articleBody)) { |
21 return; | 20 return; |
22 } | 21 } |
23 | 22 |
23 var toc = sidebar.querySelector('#toc'); | |
24 var tocOffsetTop = sidebar.offsetParent.offsetTop + toc.offsetTop; | |
25 | |
24 function addPermalink(el) { | 26 function addPermalink(el) { |
25 el.classList.add('has-permalink'); | 27 el.classList.add('has-permalink'); |
26 var id = el.id || el.textContent.toLowerCase().replace(' ', '-'); | 28 var id = el.id || el.textContent.toLowerCase().replace(' ', '-'); |
27 el.insertAdjacentHTML('beforeend', | 29 el.insertAdjacentHTML('beforeend', |
28 '<a class="permalink" title="Permalink" href="#' + id + '">#</a>'); | 30 '<a class="permalink" title="Permalink" href="#' + id + '">#</a>'); |
29 } | 31 } |
30 | 32 |
31 // Add permalinks to heading elements. | 33 // Add permalinks to heading elements. |
32 function addPermalinkHeadings(container) { | 34 function addPermalinkHeadings(container) { |
33 if (container) { | 35 if (container) { |
34 ['h2','h3','h4'].forEach(function(h, i) { | 36 ['h2','h3','h4'].forEach(function(h, i) { |
35 [].forEach.call(container.querySelectorAll(h), addPermalink); | 37 [].forEach.call(container.querySelectorAll(h), addPermalink); |
36 }); | 38 }); |
37 } | 39 } |
38 } | 40 } |
39 | 41 |
42 function toggleStickySidenav(){ | |
43 toc.classList.toggle('sticky', window.scrollY >= tocOffsetTop); | |
44 } | |
45 | |
40 function onScroll(e) { | 46 function onScroll(e) { |
41 window.scrollY >= sidebarOffsetTop ? sidebar.classList.add('sticky') : | 47 toggleStickySidenav(); |
42 sidebar.classList.remove('sticky'); | |
43 } | 48 } |
44 | 49 |
45 function onMediaQuery(e) { | 50 function onMediaQuery(e) { |
46 if (e.matches) { | 51 if (e.matches) { |
47 // On tablet & desktop, show permalinks, manage TOC position. | 52 // On tablet & desktop, show permalinks, manage TOC position. |
48 document.body.classList.remove('no-permalink'); | 53 document.body.classList.remove('no-permalink'); |
49 sidebarOffsetTop = sidebar.offsetParent.offsetTop | 54 tocOffsetTop = sidebar.offsetParent.offsetTop + toc.offsetTop; |
not at google - send to devlin
2014/06/05 20:35:39
so yeah... re-setting this global variable implies
pearlchen
2014/06/05 21:15:47
A get, or a set?
e.g.
function updateTocOffsetTo
not at google - send to devlin
2014/06/05 22:28:35
a get; try to take away the global variable
| |
50 document.addEventListener('scroll', onScroll); | 55 document.addEventListener('scroll', onScroll); |
51 } else { | 56 } else { |
52 // On mobile, hide permalinks. TOC is hidden, doesn't need to scroll. | 57 // On mobile, hide permalinks. TOC is hidden, doesn't need to scroll. |
53 document.body.classList.add('no-permalink'); | 58 document.body.classList.add('no-permalink'); |
54 document.removeEventListener('scroll', onScroll); | 59 document.removeEventListener('scroll', onScroll); |
55 } | 60 } |
56 } | 61 } |
57 | 62 |
58 // Toggle collapsible sections (mobile). | 63 // Toggle collapsible sections (mobile). |
59 articleBody.addEventListener('click', function(e) { | 64 articleBody.addEventListener('click', function(e) { |
60 if (e.target.localName == 'h2' && !isLargerThanMobileQuery.matches) { | 65 if (e.target.localName == 'h2' && !isLargerThanMobileQuery.matches) { |
61 e.target.parentElement.classList.toggle('active'); | 66 e.target.parentElement.classList.toggle('active'); |
62 } | 67 } |
63 }); | 68 }); |
64 | 69 |
65 sidebar.querySelector('#toc').addEventListener('click', function(e) { | 70 toc.addEventListener('click', function(e) { |
66 var parent = e.target.parentElement; | 71 // React only if clicking on a toplevel menu anchor item |
67 if (e.target.localName == 'a' && parent.classList.contains('toplevel')) { | 72 // that is not currently open |
68 // Allow normal link click if h2 toplevel heading doesn't have h3s. | 73 if (e.target.classList.contains('hastoc') && |
69 if (parent.querySelector('.toc')) { | 74 !e.target.parentElement.classList.contains('active')) { |
70 e.preventDefault(); | 75 e.stopPropagation(); |
71 parent.classList.toggle('active'); | 76 |
72 } | 77 // close any previously open subnavs |
78 [].forEach.call(toc.querySelectorAll('.active'), function(li) { | |
79 li.classList.remove('active'); | |
80 }); | |
81 | |
82 // then open the clicked one | |
83 e.target.parentElement.classList.add('active'); | |
73 } | 84 } |
74 }); | 85 }); |
75 | 86 |
76 // Add +/- expander to headings with subheading children. | 87 // Add +/- expander to headings with subheading children. |
77 [].forEach.call(toc.querySelectorAll('.toplevel'), function(heading) { | 88 [].forEach.call(toc.querySelectorAll('.toplevel'), function(heading) { |
78 if (heading.querySelector('.toc')) { | 89 if (heading.querySelector('.toc')) { |
79 heading.firstChild.classList.add('hastoc'); | 90 heading.firstChild.classList.add('hastoc'); |
80 } | 91 } |
81 }); | 92 }); |
82 | 93 |
83 isLargerThanMobileQuery.addListener(onMediaQuery); | 94 isLargerThanMobileQuery.addListener(onMediaQuery); |
84 onMediaQuery(isLargerThanMobileQuery); | 95 onMediaQuery(isLargerThanMobileQuery); |
96 toggleStickySidenav(); | |
85 | 97 |
86 addPermalinkHeadings(articleBody); | 98 addPermalinkHeadings(articleBody); |
87 | 99 |
88 }()); | 100 }()); |
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