vendors/tempy.js/mark
    function mark(self, p) {
      var abs = makeAbs(self, p);
      var c = self.cache[abs];
      var m = p;
      if (c) {
        var isDir = c === "DIR" || Array.isArray(c);
        var slash = p.slice(-1) === "/";
        if (isDir && !slash)
          m += "/";
        else if (!isDir && slash)
          m = m.slice(0, -1);
        if (m !== p) {
          var mabs = makeAbs(self, m);
          self.statCache[mabs] = self.statCache[abs];
          self.cache[mabs] = self.cache[abs];
        }
      }
      return m;
    }