gistfile1.js

angular
  .module('defaultValueSelect', [])
  .controller('ExampleController', function($scope, someCalculationService) {
    $scope.data = {
      availableOptions: [
        {id: '1', name: 'Option A'},
        {id: '2', name: 'Option B'},
        {id: '3', name: 'Option C'}
      ],
      selectedOption: {id: '3', name: 'Option C'} //This sets the default value of the select in the ui
    };
    
    $scope.calculate = function(val) {
      console.log('hey', $scope.data.selectedOption);
      var calculatedData = someCalculationService.calculate($scope.data.selectedOption);
    };
  })
  .factory('someCalculationService', function() {
    return {
      calculate: function() {
        return [];
      }
    }
  });