Office Scripts

This script creates a new named range

workbook.addNamedItem 

This script selects a named range

workbook.getNamedItems 

Add-ins - Creating

workbook.names.add 

Add-ins - Selecting

workbook.getNames 

Excel.run(function (context) { 
   context.workbook.names.getItem("myData").getRange().select(); 
   return context.sync();             
}).catch(function (error) { 
   console.log(error); 
});