Ngx-translate and Ionic 3?

1. Thanks for your response. storage preference working good and it also set default language when app initlize. like if hi language it set in storage then my home page data also shows in hi langauge.
   this code working fine (you can see app.component.ts ):

this.storage.get('AppLangcode')
  .then((AppLangcode) => {
    if(AppLangcode==null){
      translate.setDefaultLang('en');
    }else{
      translate.setDefaultLang(AppLangcode);
    }
  })

2.On change language i am doing 3 tasks, adding preference to storage for future app uses. setting langauge to default and using also for current session.

see Side Menu Page language.ts

langselect(form: NgForm){
    let langselcode = this.langform.value.langcode;
    this.storage.set('AppLangcode', langselcode);
    this.translate.setDefaultLang(langselcode);
    this.translate.use(langselcode);
  }

3.i didn't get purpose of below code, do app remember my default preference without save it for future session ?

 let userLang = navigator.language.split('-')[0];
  userLang = /(hi)/gi.test(userLang) ? userLang : 'en';