code: function categorizeFrame(frame) {
      var filename = frame && frame.getFileName && frame.getFileName() && Path.normalize(frame.getFileName());
      if (!filename)
          return 'core';
      else if (filename === 'tracing.js')
          return 'tracing';
      else if (!~filename.indexOf(sep))
          return 'core';
      else if (filename.indexOf(PATH_PREFIX) !== 0)
          return 'globals';
      else if (~(filename.replace(PATH_PREFIX, '')).indexOf('node_modules'))
          return 'modules';
      else
          return 'locals';
  }
docs: /* ===================== stack chain manipulation & formating ========================