luhn-generator/update/node_modules/axe-core/lib/checks/language/valid-lang-evaluate.js

A generator of numbers that passes the validation of Luhn algorithm or Luhn formula, also known as the 'modulus 10' or 'mod 10' algorithm

import { validLangs, getBaseLang } from '../../core/utils';
import { sanitize } from '../../commons/text';

function validLangEvaluate(node, options, virtualNode) {
	const langs = (options.value ? options.value : validLangs()).map(getBaseLang);

	const invalid = [];
	options.attributes.forEach(langAttr => {
		const langVal = virtualNode.attr(langAttr);
		if (typeof langVal !== 'string') {
			return;
		}

		const baselangVal = getBaseLang(langVal);

		// Edge sets lang to an empty string when xml:lang is set
		// so we need to ignore empty strings here
		if (
			(baselangVal !== '' && langs.indexOf(baselangVal) === -1) ||
			// whitespace only lang value is invalid
			(langVal !== '' && !sanitize(langVal))
		) {
			invalid.push(langAttr + '="' + virtualNode.attr(langAttr) + '"');
		}
	});

	if (invalid.length) {
		this.data(invalid);
		return true;
	}

	return false;
}

export default validLangEvaluate;