code: function (objects) {
  
          var o, propName, props = [];
          for (o in objects) {
            for (propName in objects[o]) {
              if ((objects[o].hasOwnProperty(propName))
                  && (props.indexOf(propName) < 0)
                  && (typeof objects[o][propName] !== 'function')) {
  
                props.push(propName);
              }
            }
          }
          return props;
        }
docs: $.csv.helpers.collectPropertyNames(objectsArray)
  Collects all unique property names from all passed objects.
  
  @param {Array} objects Objects to collect properties from.
  
  Returns an array of property names (array will be empty,
  if objects have no own properties).