mirror of
https://github.com/StarCitizenTools/mediawiki-skins-Citizen.git
synced 2024-11-18 03:41:50 +00:00
54 lines
1.5 KiB
JavaScript
54 lines
1.5 KiB
JavaScript
/*
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* Citizen - ToC JS
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* https://starcitizen.tools
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*/
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/**
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* Add active HTML class to items in table of content based on user viewport.
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*
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* @constructor
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*/
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function intersectionHandler() {
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var sections = document.querySelectorAll( '.mw-headline' ),
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htmlStyles = window.getComputedStyle( document.documentElement ),
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scrollPaddingTop = htmlStyles.getPropertyValue( 'scroll-padding-top' ),
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// Align with scroll offset set in CSS
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marginTop = "-" + scrollPaddingTop,
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id, id2, toclink, node, active;
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for (let i = 0; i < sections.length; i++) {
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const observer = new IntersectionObserver( ( entry ) => {
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if ( entry[ 0 ].isIntersecting ) {
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id = sections[i].id;
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// Try the ID of the span before
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if ( sections[i].previousSibling !== null ) {
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id2 = sections[i].previousSibling.id || '';
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}
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toclink = document.querySelector( "a[href='#" + id + "']" ) || document.querySelector( "a[href='#" + id2 + "']" );
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node = toclink.parentNode;
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active = document.querySelector( '.active' );
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if ( active !== null ) {
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active.classList.remove( 'active' );
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}
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if ( node !== null ) {
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node.classList.add( 'active' );
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}
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}
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}, {
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// Will break in viewport with short height
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// But calculating bottom margin on the fly is too costly
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rootMargin: marginTop + " 0px -85% 0px"
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} );
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observer.observe( sections[i] );
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}
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}
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function main() {
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// Check for has-toc class since it is loaded way before #toc is present
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if ( document.body.classList.contains( 'skin-citizen-has-toc' ) ) {
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intersectionHandler();
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}
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}
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main();
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