如何将JavaScript代码转换为Promise，全部输入类型脚本

这是我的项目代码，我需要将它从AngularJs迁移到Angular2+，这是JS中的服务文件，需要在TS服务文件上迁移

function initRegionSettings() {
      var promises = {};
      var dcaRegionSettingsPromise = $q.defer();
      promises.appSettings = AppSettingService.getAppSettingPromise();
      promises.navigationModel = BreadCrumbHelper.getNavigationPromise();


      function onSuccess(responses) {
        var countryId = $rootScope.locale.localeID.split(lowLine)[1]; //get country code from locale info e.g., en-IN
        regionSettings.HYPHEN = hyphen;
        regionSettings.localeId = $rootScope.locale.id;
        regionSettings.selectedCountry = SharedService.getRegionFromCountrySet(countryId);
        dcaRegionSettingsPromise.resolve(regionSettings);
      }


      function onError(error) {
        $log.error('Unable to load the import format settings' + error);
        dcaRegionSettingsPromise.reject();
      }

      $q.all(promises).then(onSuccess, onError);
      return dcaRegionSettingsPromise.promise;
    }