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Original file line number | Diff line number | Diff line change |
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@@ -1,196 +1,106 @@ | ||
$(document).ready(function() { | ||
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/** | ||
* TODO: Refactor with intent toward pure functions. Mutation of state can lead to bugs and difficult debugging. | ||
*/ | ||
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var toc = navData.toc; | ||
var flatToc = navData.flatToc.reverse(); | ||
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function collectNodes(tocMap) { | ||
var tocNodes = {}; | ||
tocMap.map(function(node, index) { | ||
var sectionNode = $('#' + node.section); | ||
var tocSubsections = {}; | ||
tocItem = {section: sectionNode}; | ||
var subsectionNodes; | ||
if (node.subsections) { | ||
subsectionNodes = (collectNodes(node.subsections)); | ||
tocItem.subsections = subsectionNodes; | ||
} | ||
tocNodes[node.section] = tocItem; | ||
}); | ||
return tocNodes; | ||
} | ||
var tocItems = collectNodes(toc); | ||
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function collectNodesFlat(tocMap, obj) { | ||
var collect = obj || {}; | ||
tocMap.map(function(node, index) { | ||
var sectionNode = $('#' + node.section); | ||
tocItem = {section: sectionNode}; | ||
if (node.subsections) { | ||
subsectionNodes = (collectNodesFlat(node.subsections, collect)); | ||
} | ||
collect[node.section] = sectionNode; | ||
}); | ||
return collect; | ||
} | ||
var tocFlat = collectNodesFlat(toc); | ||
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var prevSectionToken; | ||
var prevSubsectionToken; | ||
var activeTokensObj = {}; | ||
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function scrollActions(scrollPosition) { | ||
var activeSection = checkNodePositions(toc, tocFlat, scrollPosition); | ||
var activeSubSection, | ||
prevL1Nav, | ||
currL1Nav, | ||
prevL2Nav, | ||
currL2Nav; | ||
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// No active section - return existing activeTokensObj (may be empty) | ||
if (!activeSection) { | ||
return activeTokensObj; | ||
} | ||
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/** | ||
* This block deals with L1Nav sections | ||
*/ | ||
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// If no previous token, set previous to current active and show L1Nav | ||
if (!prevSectionToken) { | ||
prevSectionToken = activeSection.token; | ||
currL1Nav = getNavNode(activeSection.token); | ||
currL1Nav.show('fast'); | ||
} | ||
// If active is not the same as previous, hide previous L1Nav and show current L1Nav; set previous to current | ||
else if (activeSection.token !== prevSectionToken) { | ||
prevL1Nav = getNavNode(prevSectionToken); | ||
currL1Nav = getNavNode(activeSection.token); | ||
prevL1Nav.hide('fast'); | ||
currL1Nav.show('fast'); | ||
prevSectionToken = activeSection.token; | ||
} | ||
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/** | ||
* This block deals with L2Nav subsections | ||
*/ | ||
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// If there is a subsections array and it has a non-zero length, set active subsection | ||
if (activeSection.subsections && activeSection.subsections.length !== 0) { | ||
activeSubSection = checkNodePositions(activeSection.subsections, tocFlat, scrollPosition); | ||
if (activeSubSection) { | ||
if (!prevSubsectionToken) { | ||
prevSubsectionToken = activeSubSection.token; | ||
currL2Nav = getNavNode(activeSubSection.token); | ||
currL2Nav.show('fast'); | ||
} else if (activeSubSection.token !== prevSubsectionToken) { | ||
prevL2Nav = getNavNode(prevSubsectionToken); | ||
currL2Nav = getNavNode(activeSubSection.token); | ||
prevL2Nav.hide('fast'); | ||
currL2Nav.show('fast'); | ||
prevSubsectionToken = activeSubSection.token; | ||
} | ||
} else { | ||
prevL2Nav = getNavNode(prevSubsectionToken); | ||
prevL2Nav.hide('fast'); | ||
prevSubsectionToken = null; | ||
} | ||
} | ||
activeTokensObj.L1 = prevSectionToken; | ||
activeTokensObj.L2 = prevSubsectionToken; | ||
return activeTokensObj; | ||
jQuery(function($) { | ||
// tocItems are headings in the main content area that have a representation in the TOC | ||
// (not all headings are present in the TOC). | ||
let tocItems = $('#page-content-wrapper .toc-item'); | ||
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function getCurrentlyVisibleSection(scrollPosition) { | ||
// Walk the list from the bottom up and check; | ||
// each TOC item is the immediate child of a <div> that | ||
// carries the TOC item's ID. | ||
for (let i = tocItems.length - 1; i >= 0; --i) { | ||
let item = $(tocItems.get(i)); | ||
let offsetTop = item.offset().top - 50; | ||
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if (scrollPosition >= offsetTop) { | ||
return item.parent().attr('id'); | ||
} | ||
} | ||
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/** | ||
* Checks for active elements by scroll position | ||
*/ | ||
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var prevElemToken; | ||
var activeElemToken; | ||
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function checkActiveElement(items, scrollPosition) { | ||
var offset = 50; | ||
var offsetScroll = scrollPosition + offset; | ||
var visibleNode; | ||
for (var i = 0; i < items.length; i++) { | ||
var token = items[i]; | ||
var node = getHeadingNode(token); | ||
if (offsetScroll >= node.offset().top) { | ||
activeElemToken = token; | ||
} | ||
} | ||
if (!prevElemToken) { | ||
getNavElemNode(activeElemToken).addClass('selected'); | ||
prevElemToken = activeElemToken; | ||
return; | ||
} | ||
if (activeElemToken !== prevElemToken) { | ||
getNavElemNode(prevElemToken).removeClass('selected'); | ||
getNavElemNode(activeElemToken).addClass('selected'); | ||
prevElemToken = activeElemToken; | ||
} | ||
return activeElemToken; | ||
} | ||
return null; | ||
} | ||
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function getHeadingNode(token) { | ||
return $('#' + token); | ||
} | ||
function updateNavigationState(visibleSection) { | ||
let selectedLink = $('#navigation a.selected'); | ||
let selectedSection = selectedLink.length === 0 ? null : selectedLink.attr('href').replace(/#/, ''); | ||
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function getNavNode(token) { | ||
return $('#' + token + '-nav'); | ||
// nothing to do :) | ||
if (visibleSection === selectedSection) { | ||
return; | ||
} | ||
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function getNavElemNode(token) { | ||
return $('#sidebar-wrapper > ul a[href="#' + token + '"]'); | ||
// un-select whatever was previously selected | ||
if (selectedLink.length > 0) { | ||
selectedLink.removeClass('selected'); | ||
} | ||
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function checkNodePositions(nodes, flatNodeMap, scrollPosition) { | ||
var activeNode; | ||
for (var i = 0; i < nodes.length; i++) { | ||
var item = nodes[i]; | ||
var node = flatNodeMap[item.section]; | ||
var nodeTop = node.offset().top - 50; | ||
if (scrollPosition >= nodeTop) { | ||
activeNode = {token: item.section, node: node}; | ||
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if (item.subsections) { | ||
activeNode.subsections = item.subsections; | ||
} | ||
break; | ||
} | ||
} | ||
return activeNode; | ||
if (visibleSection !== null) { | ||
// show the leaf node in the navigation for the activeSection, plus | ||
// all nodes that lead to it (in a->b->c->d, if c is active, show | ||
// b and c because a is always shown already). | ||
let activeSectionLink = '#' + visibleSection; | ||
let link = $('#navigation a[href="' + activeSectionLink + '"]'); | ||
let listItem = link.parent(); | ||
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link.addClass('selected'); | ||
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while (listItem.data('level') > 1) { | ||
let ul = listItem.parent(); | ||
ul.show('fast'); | ||
listItem = ul.parent(); | ||
} | ||
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// expand the currently selected item, i.e. do not just show the | ||
// parent path, but also the immediate child <ul> | ||
link.parent().children('ul').show('fast'); | ||
} | ||
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function scrollToNav(token) { | ||
setTimeout(function() { | ||
var scrollPosition = $(window).scrollTop(); | ||
var activeSectionTokens = scrollActions(scrollPosition); | ||
var activeElemToken = checkActiveElement(flatToc, scrollPosition); | ||
var navNode = $('#sidebar-wrapper > ul a[href="#' + token + '"]'); | ||
$('#sidebar-wrapper').scrollTo(navNode, {duration: 'fast', axis: 'y'}); | ||
}, 200); | ||
} | ||
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$(window).on('hashchange', function(event) { | ||
var scrollPosition = $(window).scrollTop(); | ||
var activeSectionTokens = scrollActions(scrollPosition); | ||
var activeElemToken = checkActiveElement(flatToc, scrollPosition); | ||
var scrollToken = activeSectionTokens.L2 ? activeSectionTokens.L2 : activeSectionTokens.L1; | ||
scrollToNav(scrollToken); | ||
var token = location.hash.slice(1); | ||
// collapse all sub tree that are not required to show the currently | ||
// selected section (i.e. has no .selected in its children, is not | ||
// the direct descendant of the currently selected item (which we | ||
// just expanded) and is not the top level). | ||
$('#navigation ul:visible').each(function() { | ||
let list = $(this); | ||
if (list.find('.selected').length > 0) { | ||
return; | ||
} | ||
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let listItem = list.parent(); | ||
if (listItem.data('level') <= 1) { | ||
return; | ||
} | ||
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let link = listItem.children('a'); | ||
if (link.hasClass('selected')) { | ||
return; | ||
} | ||
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list.hide('fast'); | ||
}); | ||
} | ||
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var scrollPosition = $(window).scrollTop(); | ||
scrollActions(scrollPosition); | ||
checkActiveElement(flatToc, scrollPosition); | ||
// TODO: prevent scroll on sidebar from propagating to window | ||
$(window).on('scroll', function(event) { | ||
var scrollPosition = $(window).scrollTop(); | ||
var activeSectionTokens = scrollActions(scrollPosition); | ||
var activeElemToken = checkActiveElement(flatToc, scrollPosition); | ||
}); | ||
}); | ||
let navScrollTimeout; | ||
function scrollToNav(currentSection) { | ||
// debounce to prevent too many scrolls in the sidebar | ||
if (navScrollTimeout) { | ||
clearTimeout(navScrollTimeout); | ||
} | ||
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navScrollTimeout = setTimeout(function() { | ||
let navNode = $('#navigation a[href="#' + currentSection + '"]'); | ||
$('#sidebar-wrapper').scrollTo(navNode, {duration: 'fast', axis: 'y', over: {top: -1}}); | ||
}, 200); | ||
} | ||
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function repaint() { | ||
let scrollPosition = $(window).scrollTop(); | ||
let currentSection = getCurrentlyVisibleSection(scrollPosition); | ||
updateNavigationState(currentSection); | ||
scrollToNav(currentSection); | ||
} | ||
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// update navigation whenever scrolling happens | ||
$(window).on('scroll', repaint); | ||
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// perform an initial update on the navigation | ||
repaint(); | ||
}); |