jodit/src/core/helpers/default-language.ts

Jodit is awesome and usefully wysiwyg editor with filebrowser

/*!
 * Jodit Editor (https://xdsoft.net/jodit/)
 * Released under MIT see LICENSE.txt in the project root for license information.
 * Copyright (c) 2013-2020 Valeriy Chupurnov. All rights reserved. https://xdsoft.net
 */

import { isString } from './checker';

/**
 * Try define user language
 *
 * @param language
 * @param defaultLanguage
 */
export const defaultLanguage = (
	language?: string,
	defaultLanguage: string = 'en'
): string => {
	if (language !== 'auto' && isString(language)) {
		return language;
	}

	if (document.documentElement && document.documentElement.lang) {
		return document.documentElement.lang;
	}

	if (navigator.language) {
		return navigator.language.substr(0, 2);
	}

	return defaultLanguage;
};