code: function $$core$$log10Floor (n) {
          // ES6 provides the more accurate Math.log10
          if (typeof Math.log10 === 'function')
              return Math.floor(Math.log10(n));
  
          var x = Math.round(Math.log(n) * Math.LOG10E);
          return x - (Number('1e' + x) > n);
      }
docs: Helper functions ================ 
  A function to deal with the inaccuracy of calculating log10 in pre-ES6
  JavaScript environments. Math.log(num) / Math.LN10 was responsible for
  causing issue #62.