File size: 1,754 Bytes
4e1096a | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 | import { FoliateView } from '@/types/view';
import { throttle } from './throttle';
import { debounce } from './debounce';
export const handleA11yNavigation = (
view: FoliateView | null,
document: Document,
index: number,
) => {
if (!view) return;
const state = {
skipInitial: true,
hasRecentRelocate: false,
relocateTimer: null as ReturnType<typeof setTimeout> | null,
};
const markRelocateEnd = debounce(() => {
state.hasRecentRelocate = false;
}, 2000);
const markRelocated = () => {
state.hasRecentRelocate = true;
markRelocateEnd();
};
const throttledMarkRelocated = throttle(markRelocated, 1000);
view.renderer.addEventListener('scroll', throttledMarkRelocated, { passive: true });
view.renderer.addEventListener('relocate', throttledMarkRelocated);
const observer = new IntersectionObserver(
(entries) => {
if (state.skipInitial) {
state.skipInitial = false;
return;
}
if (state.hasRecentRelocate) return;
for (const entry of entries) {
if (entry.isIntersecting) {
const range = document.createRange();
range.selectNodeContents(entry.target);
const cfi = view.getCFI(index, range);
setTimeout(() => {
if (state.hasRecentRelocate) return;
const resolved = view.resolveNavigation(cfi);
view.renderer.goTo?.(resolved);
console.log('Navigating to new location from screen reader');
}, 500);
break;
}
}
},
{ threshold: 0 },
);
document.querySelectorAll('a').forEach((el) => {
el.setAttribute('tabindex', '-1');
});
document.querySelectorAll('p').forEach((el) => {
observer.observe(el);
});
};
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