if ('IntersectionObserver' in window &&
'IntersectionObserverEntry' in window &&
'intersectionRatio' in window.IntersectionObserverEntry.prototype) {
- $(document).ready(function () {
- // fetch all the headings.
- let headings = document.querySelector('.page-content').querySelectorAll('h1, h2, h3, h4, h5, h6');
- // if headings are present, add observers.
- if (headings.length > 0) {
- addNavObserver(headings);
- }
- });
+ addPageHighlighting();
}
- let $pageNav = null;
- function addNavObserver(headings) {
- // Setup the intersection observer.
- // margin top = -25px to trigger the threshold change before the heading
- // has completely left the viewport on the top.
- let intersectOpts = {
- rootMargin: '-25px 0px 0px 0px',
- threshold: 1.0
- }
- $pageNav = $('.sidebar-page-nav');
- let pageNavObserver = new IntersectionObserver(cbHeadingVisible, intersectOpts);
-
- // observe each heading
- for (let i = 0; i !== headings.length; ++i) {
- pageNavObserver.observe(headings[i]);
- }
- }
-
- function cbHeadingVisible(entries, observer) {
- let element = null;
- for (let i = 0; i !== entries.length; ++i) {
- let currentEntry = entries[i];
- // check if its currently visible and its distance from top of viewport is less than 100
- if (currentEntry.intersectionRatio <= 1 && currentEntry.boundingClientRect.y < 100) {
- element = currentEntry.target;
- } else {
- break;
- }
- }
- if (!element) {
- return;
- }
- let elementId = element.id;
- $pageNav.find('a').removeClass('current-heading');
- $pageNav.find('a[href="#' + elementId + '"]').addClass('current-heading');
+ function addPageHighlighting() {
+ let $pageNav = null;
+
+ $(document).ready(function () {
+ // fetch all the headings.
+ let headings = document.querySelector('.page-content').querySelectorAll('h1, h2, h3, h4, h5, h6');
+ // if headings are present, add observers.
+ if (headings.length > 0) {
+ addNavObserver(headings);
+ }
+ });
+
+ function addNavObserver(headings) {
+ // Setup the intersection observer.
+ // margin top = -35px to trigger the threshold change before the heading
+ // has completely left the viewport on the top.
+ let intersectOpts = {
+ rootMargin: '-35px 0px 0px 0px',
+ threshold: 1.0
+ }
+ $pageNav = $('.sidebar-page-nav');
+ let pageNavObserver = new IntersectionObserver(cbHeadingVisible, intersectOpts);
+
+ // observe each heading
+ for (let i = 0; i !== headings.length; ++i) {
+ pageNavObserver.observe(headings[i]);
+ }
+ }
+
+ function cbHeadingVisible(entries, observer) {
+ let element = null;
+ for (let i = 0; i !== entries.length; ++i) {
+ let currentEntry = entries[i];
+ // check if its currently visible and its distance from top of viewport is less than 100
+ if (currentEntry.intersectionRatio <= 1 && currentEntry.boundingClientRect.y < 100) {
+ element = currentEntry.target;
+ } else {
+ break;
+ }
+ }
+ if (!element) {
+ return;
+ }
+ let elementId = element.id;
+ $pageNav.find('a').removeClass('current-heading');
+ $pageNav.find('a[href="#' + elementId + '"]').addClass('current-heading');
+ }
}
-
};
module.exports = setupPageShow;
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