next
Version:
The React Framework
64 lines (63 loc) • 2.76 kB
JavaScript
import { useEffect, useRef, useState } from 'react';
import { createPortal } from 'react-dom';
const ANNOUNCER_TYPE = 'next-route-announcer';
const ANNOUNCER_ID = '__next-route-announcer__';
function getAnnouncerNode() {
var _existingAnnouncer_shadowRoot;
const existingAnnouncer = document.getElementsByName(ANNOUNCER_TYPE)[0];
if (existingAnnouncer == null ? void 0 : (_existingAnnouncer_shadowRoot = existingAnnouncer.shadowRoot) == null ? void 0 : _existingAnnouncer_shadowRoot.childNodes[0]) {
return existingAnnouncer.shadowRoot.childNodes[0];
} else {
const container = document.createElement(ANNOUNCER_TYPE);
container.style.cssText = 'position:absolute';
const announcer = document.createElement('div');
announcer.ariaLive = 'assertive';
announcer.id = ANNOUNCER_ID;
announcer.role = 'alert';
announcer.style.cssText = 'position:absolute;border:0;height:1px;margin:-1px;padding:0;width:1px;clip:rect(0 0 0 0);overflow:hidden;white-space:nowrap;word-wrap:normal';
// Use shadow DOM here to avoid any potential CSS bleed
const shadow = container.attachShadow({
mode: 'open'
});
shadow.appendChild(announcer);
document.body.appendChild(container);
return announcer;
}
}
export function AppRouterAnnouncer(param) {
let { tree } = param;
const [portalNode, setPortalNode] = useState(null);
useEffect(()=>{
const announcer = getAnnouncerNode();
setPortalNode(announcer);
return ()=>{
const container = document.getElementsByTagName(ANNOUNCER_TYPE)[0];
if (container == null ? void 0 : container.isConnected) {
document.body.removeChild(container);
}
};
}, []);
const [routeAnnouncement, setRouteAnnouncement] = useState('');
const previousTitle = useRef(undefined);
useEffect(()=>{
let currentTitle = '';
if (document.title) {
currentTitle = document.title;
} else {
const pageHeader = document.querySelector('h1');
if (pageHeader) {
currentTitle = pageHeader.innerText || pageHeader.textContent || '';
}
}
// Only announce the title change, but not for the first load because screen
// readers do that automatically.
if (previousTitle.current !== undefined && previousTitle.current !== currentTitle) {
setRouteAnnouncement(currentTitle);
}
previousTitle.current = currentTitle;
}, [
tree
]);
return portalNode ? /*#__PURE__*/ createPortal(routeAnnouncement, portalNode) : null;
}
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