code: function(data) {
          var self = this;
  
          self.archive = null;
          self.sharedStrings = [];
          self.sharedStringsLookup = {};
  
          if(data) {
              self.loadTemplate(data);
          }
      }
docs: Create a new workbook. Either pass the raw data of a .xlsx file,
  or call `loadTemplate()` later.