91 lines
2.5 KiB
JavaScript
91 lines
2.5 KiB
JavaScript
const
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FEATURE_VISIBLE_CLASS = 'vector-sticky-header-visible',
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FEATURE_TEST_GROUP = 'stickyHeaderEnabled',
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SCROLL_HOOK = 'vector.page_title_scroll',
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SCROLL_CONTEXT_ABOVE = 'scrolled-above-page-title',
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SCROLL_CONTEXT_BELOW = 'scrolled-below-page-title',
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SCROLL_ACTION = 'scroll-to-top';
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/**
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* Determine if user is in test group to experience feature.
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*
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* @param {string} bucket the bucket name the user is assigned
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* @param {string} targetGroup the target test group to experience feature
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* @return {boolean} true if the user should experience feature
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*/
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function isInTestGroup( bucket, targetGroup ) {
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return bucket === targetGroup;
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}
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/**
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* Show the feature based on test group.
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*
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* @param {HTMLElement} element target feature
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* @param {string} group A/B test bucket of the user
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*/
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function onShowFeature( element, group ) {
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if ( isInTestGroup( group, FEATURE_TEST_GROUP ) ) {
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// eslint-disable-next-line mediawiki/class-doc
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element.classList.add( FEATURE_VISIBLE_CLASS );
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}
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}
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/**
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* Hide the feature based on test group.
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*
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* @param {HTMLElement} element target feature
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* @param {string} group A/B test bucket of the user
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*/
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function onHideFeature( element, group ) {
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if ( isInTestGroup( group, FEATURE_TEST_GROUP ) ) {
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// eslint-disable-next-line mediawiki/class-doc
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element.classList.remove( FEATURE_VISIBLE_CLASS );
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}
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}
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/**
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* Fire a hook to be captured by WikimediaEvents for scroll event logging.
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*
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* @param {string} direction the scroll direction
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*/
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function fireScrollHook( direction ) {
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if ( direction === 'down' ) {
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// @ts-ignore
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mw.hook( SCROLL_HOOK ).fire( { context: SCROLL_CONTEXT_BELOW } );
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} else {
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// @ts-ignore
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mw.hook( SCROLL_HOOK ).fire( {
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context: SCROLL_CONTEXT_ABOVE,
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action: SCROLL_ACTION
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} );
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}
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}
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/**
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* Create an observer for showing/hiding feature and for firing scroll event hooks.
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*
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* @param {Function} show functionality for when feature is visible
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* @param {Function} hide functionality for when feature is hidden
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* @return {IntersectionObserver}
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*/
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function initScrollObserver( show, hide ) {
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/* eslint-disable-next-line compat/compat */
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return new IntersectionObserver( function ( entries ) {
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if ( !entries[ 0 ].isIntersecting && entries[ 0 ].boundingClientRect.top < 0 ) {
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// Viewport has crossed the bottom edge of the target element.
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show();
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} else {
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// Viewport is above the bottom edge of the target element.
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hide();
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}
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} );
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}
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module.exports = {
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initScrollObserver,
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onShowFeature,
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onHideFeature,
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fireScrollHook,
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FEATURE_TEST_GROUP
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};
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