112 lines
4.1 KiB
TypeScript
112 lines
4.1 KiB
TypeScript
import { useEffect, useRef } from 'react';
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export interface SEOMeta {
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title: string;
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description: string;
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url: string;
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ogImage?: string;
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/** Module-level constant: injected once on mount, removed on unmount. */
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jsonLd?: object | object[];
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/** If true, sets robots meta to "noindex, nofollow" to prevent indexing. */
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noindex?: boolean;
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}
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function qs(selector: string): HTMLMetaElement | null {
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return document.querySelector(selector) as HTMLMetaElement | null;
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}
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/**
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* Updates document.title, meta description, OG/Twitter tags, and canonical
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* to reflect the current page. Restores originals on unmount.
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*
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* jsonLd (if provided) is injected as a <script type="application/ld+json">
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* once on mount and removed on unmount. Pass a module-level constant to avoid
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* unnecessary re-injection.
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*/
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export function useSEO({ title, description, url, ogImage, jsonLd, noindex }: SEOMeta) {
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const scriptRef = useRef<HTMLScriptElement | null>(null);
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useEffect(() => {
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const origTitle = document.title;
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const descEl = qs('meta[name="description"]');
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const robotsEl = qs('meta[name="robots"]');
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const ogTitleEl = qs('meta[property="og:title"]');
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const ogDescEl = qs('meta[property="og:description"]');
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const ogUrlEl = qs('meta[property="og:url"]');
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const ogImgEl = qs('meta[property="og:image"]');
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const twTitleEl = qs('meta[name="twitter:title"]');
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const twDescEl = qs('meta[name="twitter:description"]');
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const canonicalEl = document.querySelector('link[rel="canonical"]') as HTMLLinkElement | null;
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const get = (el: HTMLMetaElement | null) => el?.getAttribute('content') ?? '';
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const set = (el: HTMLMetaElement | null, v: string) => el?.setAttribute('content', v);
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const origDesc = get(descEl);
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const origRobots = get(robotsEl);
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const origOgTitle = get(ogTitleEl);
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const origOgDesc = get(ogDescEl);
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const origOgUrl = get(ogUrlEl);
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const origOgImg = get(ogImgEl);
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const origTwTitle = get(twTitleEl);
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const origTwDesc = get(twDescEl);
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const origCanonical = canonicalEl?.getAttribute('href') ?? '';
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// If no <link rel="canonical"> exists yet, create one so each SPA route
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// gets its own canonical (avoids all routes appearing to point back to /).
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let createdCanonical = false;
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let activeCanonical: HTMLLinkElement | null = canonicalEl as HTMLLinkElement | null;
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if (!activeCanonical) {
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activeCanonical = document.createElement('link') as HTMLLinkElement;
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activeCanonical.rel = 'canonical';
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document.head.appendChild(activeCanonical);
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createdCanonical = true;
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}
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// Apply
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document.title = title;
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set(descEl, description);
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if (noindex) {
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set(robotsEl, 'noindex, nofollow');
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}
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set(ogTitleEl, title);
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set(ogDescEl, description);
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set(ogUrlEl, url);
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if (ogImage) set(ogImgEl, ogImage);
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set(twTitleEl, title);
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set(twDescEl, description);
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activeCanonical.setAttribute('href', url);
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// Inject JSON-LD once (module-level constants don't change)
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if (jsonLd && !scriptRef.current) {
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const script = document.createElement('script');
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script.type = 'application/ld+json';
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script.setAttribute('data-seo-page', '1');
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script.textContent = JSON.stringify(Array.isArray(jsonLd) ? jsonLd : [jsonLd]);
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document.head.appendChild(script);
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scriptRef.current = script;
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}
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return () => {
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document.title = origTitle;
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set(descEl, origDesc);
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if (noindex) set(robotsEl, origRobots);
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set(ogTitleEl, origOgTitle);
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set(ogDescEl, origOgDesc);
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set(ogUrlEl, origOgUrl);
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if (ogImage) set(ogImgEl, origOgImg);
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set(twTitleEl, origTwTitle);
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set(twDescEl, origTwDesc);
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if (createdCanonical && activeCanonical && document.head.contains(activeCanonical)) {
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document.head.removeChild(activeCanonical);
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} else {
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activeCanonical?.setAttribute('href', origCanonical);
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}
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if (scriptRef.current) {
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document.head.removeChild(scriptRef.current);
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scriptRef.current = null;
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}
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};
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// eslint-disable-next-line react-hooks/exhaustive-deps
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}, [title, description, url, ogImage, noindex]);
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}
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