computeCurrentLocale() — astro Function Reference

Source Code

packages/astro/src/core/render-context.ts lines 803–849

	computeCurrentLocale() {
		const {
			url,
			pipeline: { i18n },
			routeData,
		} = this;
		if (!i18n) return;

		const { defaultLocale, locales, strategy } = i18n;

		const fallbackTo =
			strategy === 'pathname-prefix-other-locales' || strategy === 'domains-prefix-other-locales'
				? defaultLocale
				: undefined;

		if (this.#currentLocale) {
			return this.#currentLocale;
		}

		let computedLocale;
		if (isRouteServerIsland(routeData)) {
			let referer = this.request.headers.get('referer');
			if (referer) {
				if (URL.canParse(referer)) {
					referer = new URL(referer).pathname;
				}
				computedLocale = computeCurrentLocale(referer, locales, defaultLocale);
			}
		} else {
			// For SSG we match the route naively, for dev we handle fallback on 404, for SSR we find route from fallbackRoutes
			let pathname = routeData.pathname;
			if (!routeData.pattern.test(url.pathname)) {
				for (const fallbackRoute of routeData.fallbackRoutes) {
					if (fallbackRoute.pattern.test(url.pathname)) {
						pathname = fallbackRoute.pathname;
						break;
					}
				}
			}
			pathname = pathname && !isRoute404or500(routeData) ? pathname : url.pathname;
			computedLocale = computeCurrentLocale(pathname, locales, defaultLocale);
		}

		this.#currentLocale = computedLocale ?? fallbackTo;

		return this.#currentLocale;
	}