Select default lang based on browser lang

For issue #154.

src/App.vue

@@ -43,6 +43,24 @@ export default {
     };
   },
   beforeMount() {
+    if (!this.$store.state.language) {
+      // No language set, default to browser language?
+      var browserLang = (
+        navigator.language ||
+        navigator.userLanguage ||
+        ""
+      ).toLowerCase();
+      if (this.$i18n.messages[browserLang]) {
+        this.$store.commit("setLanguage", browserLang);
+      } else if (browserLang.includes("-")) {
+        // Try with language name only.
+        let lang = browserLang.split("-")[0];
+        if (this.$i18n.messages[lang]) {
+          this.$store.commit("setLanguage", lang);
+        }
+      }
+    }
+
     // Set language
     this.$i18n.locale = this.$store.state.language || "en";
   },

src/store/index.js

@@ -64,7 +64,7 @@ const vuexPersistSessionStorage = new VuexPersist({
 const defaultUseSessionStorage = (sessionStorage.getItem('user') != null);
 
 export default new Vuex.Store({
-    state: { language: 'en', currentRoomId: null, auth: null, tempuser: null, useLocalStorage: !defaultUseSessionStorage },
+    state: { language: null, currentRoomId: null, auth: null, tempuser: null, useLocalStorage: !defaultUseSessionStorage },
     mutations: {
         loginSuccess(state, user) {
             state.auth.status.loggedIn = true;