@formatjs/intl-datetimeformat/should-polyfill.js

Intl.DateTimeFormat polyfill

import { match } from "@formatjs/intl-localematcher";
import { supportedLocales } from "./supported-locales.generated.js";
function supportsDateStyle() {
	try {
		return !!new Intl.DateTimeFormat(undefined, { dateStyle: "short" }).resolvedOptions().dateStyle;
	} catch {
		return false;
	}
}
/**
* https://bugs.chromium.org/p/chromium/issues/detail?id=865351
*/
function hasChromeLt71Bug() {
	try {
		return new Intl.DateTimeFormat("en", {
			hourCycle: "h11",
			hour: "numeric"
		}).formatToParts(0)[2].type !== "dayPeriod";
	} catch {
		return false;
	}
}
/**
* Node 14's version of Intl.DateTimeFormat does not throw
* when dateStyle/timeStyle is used with other options.
* This was fixed in newer V8 versions
*/
function hasUnthrownDateTimeStyleBug() {
	try {
		return !!new Intl.DateTimeFormat("en", {
			dateStyle: "short",
			hour: "numeric"
		}).format(new Date(0));
	} catch {
		return false;
	}
}
function supportedLocalesOf(locale) {
	if (!locale) {
		return true;
	}
	const locales = Array.isArray(locale) ? locale : [locale];
	return Intl.DateTimeFormat.supportedLocalesOf(locales).length === locales.length;
}
export function shouldPolyfill(locale = "en") {
	if (!("DateTimeFormat" in Intl) || !("formatToParts" in Intl.DateTimeFormat.prototype) || !("formatRange" in Intl.DateTimeFormat.prototype) || hasChromeLt71Bug() || hasUnthrownDateTimeStyleBug() || !supportsDateStyle() || !supportedLocalesOf(locale)) {
		return locale ? match([locale], supportedLocales, "en") : undefined;
	}
}