// using -> "selector": "html[lang][xml\\:lang]" to narrow down html with lang and xml:lang attributes

// get primary base language for each of the attributes
const { getBaseLang } = axe.utils;
const primaryLangValue = getBaseLang(node.getAttribute('lang'));
const primaryXmlLangValue = getBaseLang(node.getAttribute('xml:lang'));

// ensure that the value specified is valid lang for both `lang` and `xml:lang`
return (
	axe.utils.validLangs().includes(primaryLangValue) &&
	axe.utils.validLangs().includes(primaryXmlLangValue)
);