code: function isBlank(char) {
          return (char === ' ' ||
              char === '\f' ||
              char === '\n' ||
              char === '\r' ||
              char === '\t' ||
              char === '\v' ||
              char === '\u00A0' ||
              char === '\u2028' ||
              char === '\u2029');
      }
docs: test a char whether a whitespace char