text: export function sort_by (field, reverse, primer){
      var key = primer ?
          function(x) {return primer(x[field])} :
          function(x) {return x[field]};
  
      reverse = !reverse ? 1 : -1;
  
      return function (a, b) {
          return a = key(a), b = key(b), reverse * ((a > b) - (b > a));
      }
  }
  