🐛 fix invalid language tag when passing locale argument to iframe

source/i18n.js

@@ -1,14 +1,13 @@
-import { I18nextProvider } from 'react-i18next'
 import i18next from 'i18next'
 import queryString from 'query-string'
 
-import { getIframeOption } from './utils'
+import { getIframeOption, parseDataAttributes } from './utils'
 import enTranslations from './locales/en.yaml'
 
 let lang =
 	getIframeOption('lang') ||
 	queryString.parse(location.search)['lang'] ||
-	sessionStorage['lang'] ||
+	parseDataAttributes(sessionStorage['lang']) ||
 	'fr'
 
 sessionStorage['lang'] = lang

source/utils.js

@@ -1,8 +1,21 @@
 export let capitalise0 = name => name[0].toUpperCase() + name.slice(1)
 
 export let getUrl = () => window.location.href.toString()
+
+export let parseDataAttributes = value =>
+	value === 'undefined'
+		? undefined
+		: value === null
+			? null
+			: !isNaN(value)
+				? +value
+				: /* value is a normal string */
+				  value
+
 export let getIframeOption = optionName => {
 	let url = getUrl(),
 		hasOption = url.includes(optionName + '=')
-	return hasOption && url.split(optionName + '=')[1].split('&')[0]
+	return parseDataAttributes(
+		hasOption && url.split(optionName + '=')[1].split('&')[0]
+	)
 }