<div ng-app="myApp" ng-controller="myCtrl">
  {{ (obj1.prop1 ? obj1.prop1 : '') + ' ' + (obj2.prop2 ? obj2.prop2 : '') }}
</div>

<script>
  var app = angular.module('myApp', []);
  app.controller('myCtrl', function($scope) {
    $scope.obj1 = {
      prop1: 'Hello'
    };
    $scope.obj2 = {
      prop2: 'World'
    };
  });
</script>