Protractor: Returning an array of objects from a table

I have a table with 3 columns 'firstname', 'lastname', 'birthday'. I would like to get each row and return a JSON of these 3 items like:

tableData = [ {
               firstname: element.(by.id('firstname')).getText(),
               lastname:  element.(by.id('lastname')).getText(),
               birthday:  element.(by.id('birthday')).getText()
              },
              {
               ...
              }
            ]