function getConf() { // get from database
    return Restangular.all('conf').getList().then(function(conf) {
      return conf;
    })
}

function getConfObject() {
  return promiseConf.then(confArr => {
        return _(confArr).keyBy('myConf').value();
    });
}

this.config = null;

init () {
    ...
    this.SomeService.getConfObject().then(conf => {
        this.config = do some thing with conf
    });
    ...
}

methodA () {
    // Can I be sure that in this place this.config is initialized from databse ?
}