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-rw-r--r--web_src/js/markup/anchors.js70
1 files changed, 70 insertions, 0 deletions
diff --git a/web_src/js/markup/anchors.js b/web_src/js/markup/anchors.js
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+++ b/web_src/js/markup/anchors.js
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+import {svg} from '../svg.js';
+
+const addPrefix = (str) => `user-content-${str}`;
+const removePrefix = (str) => str.replace(/^user-content-/, '');
+const hasPrefix = (str) => str.startsWith('user-content-');
+
+// scroll to anchor while respecting the `user-content` prefix that exists on the target
+function scrollToAnchor(encodedId) {
+ if (!encodedId) return;
+ const id = decodeURIComponent(encodedId);
+ const prefixedId = addPrefix(id);
+ let el = document.getElementById(prefixedId);
+
+ // check for matching user-generated `a[name]`
+ if (!el) {
+ const nameAnchors = document.getElementsByName(prefixedId);
+ if (nameAnchors.length) {
+ el = nameAnchors[0];
+ }
+ }
+
+ // compat for links with old 'user-content-' prefixed hashes
+ if (!el && hasPrefix(id)) {
+ return document.getElementById(id)?.scrollIntoView();
+ }
+
+ el?.scrollIntoView();
+}
+
+export function initMarkupAnchors() {
+ const markupEls = document.querySelectorAll('.markup');
+ if (!markupEls.length) return;
+
+ for (const markupEl of markupEls) {
+ // create link icons for markup headings, the resulting link href will remove `user-content-`
+ for (const heading of markupEl.querySelectorAll('h1, h2, h3, h4, h5, h6')) {
+ const a = document.createElement('a');
+ a.classList.add('anchor');
+ a.setAttribute('href', `#${encodeURIComponent(removePrefix(heading.id))}`);
+ a.innerHTML = svg('octicon-link');
+ heading.prepend(a);
+ }
+
+ // remove `user-content-` prefix from links so they don't show in url bar when clicked
+ for (const a of markupEl.querySelectorAll('a[href^="#"]')) {
+ const href = a.getAttribute('href');
+ if (!href.startsWith('#user-content-')) continue;
+ a.setAttribute('href', `#${removePrefix(href.substring(1))}`);
+ }
+
+ // add `user-content-` prefix to user-generated `a[name]` link targets
+ // TODO: this prefix should be added in backend instead
+ for (const a of markupEl.querySelectorAll('a[name]')) {
+ const name = a.getAttribute('name');
+ if (!name) continue;
+ a.setAttribute('name', addPrefix(a.name));
+ }
+
+ for (const a of markupEl.querySelectorAll('a[href^="#"]')) {
+ a.addEventListener('click', (e) => {
+ scrollToAnchor(e.currentTarget.getAttribute('href')?.substring(1));
+ });
+ }
+ }
+
+ // scroll to anchor unless the browser has already scrolled somewhere during page load
+ if (!document.querySelector(':target')) {
+ scrollToAnchor(window.location.hash?.substring(1));
+ }
+}