55 lines
1.4 KiB
JavaScript
55 lines
1.4 KiB
JavaScript
import { visitUrl } from './url_utility';
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/**
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* Helper function that finds the href of the fiven selector and updates the location.
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*
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* @param {String} selector
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*/
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export default function findAndFollowLink(selector) {
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const element = document.querySelector(selector);
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const link = element && element.getAttribute('href');
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if (link) {
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visitUrl(link);
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}
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}
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export function prefetchDocument(url) {
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const newPrefetchLink = document.createElement('link');
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newPrefetchLink.rel = 'prefetch';
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newPrefetchLink.href = url;
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newPrefetchLink.setAttribute('as', 'document');
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document.head.appendChild(newPrefetchLink);
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}
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export function initPrefetchLinks(selector) {
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document.querySelectorAll(selector).forEach((el) => {
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let mouseOverTimer;
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const mouseOutHandler = () => {
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if (mouseOverTimer) {
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clearTimeout(mouseOverTimer);
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mouseOverTimer = undefined;
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}
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};
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const mouseOverHandler = () => {
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el.addEventListener('mouseout', mouseOutHandler, { once: true, passive: true });
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mouseOverTimer = setTimeout(() => {
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if (el.href) prefetchDocument(el.href);
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// Only execute once
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el.removeEventListener('mouseover', mouseOverHandler, true);
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mouseOverTimer = undefined;
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}, 100);
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};
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el.addEventListener('mouseover', mouseOverHandler, {
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capture: true,
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passive: true,
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});
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});
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}
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