code: function shadowWtcTagFlag_() {
    if (!SHADOW_WTC_FLAGS_) {
      // not initialized yet
      SHADOW_WTC_FLAGS_ = {};
      SHADOW_WTC_ISPRE_ = {};
      scanOneLevel(T, '');
    }
    return [SHADOW_WTC_FLAGS_, SHADOW_WTC_ISPRE_];
  
    function scanOneLevel(aSet, sPath) {
      Object.keys(aSet).forEach(function (sKey) {
        if (!sKey || sKey[sKey.length - 1] == '_') return;
        var value = aSet[sKey];
        if ((typeof value === 'undefined' ? 'undefined' : _typeof(value)) != 'object') return;
  
        if (value.getDefaultProps) {
          var props = value.getDefaultProps(),
              iFlag = 1;
          if (props['childInline.']) {
            if (hasClass_(props.className || '', 'rewgt-unit')) iFlag = 2;else iFlag = 3;
          }
          // else iFlag = 1; // Panel(0) or Unit(1), take all of them as Unit
          if (iFlag != 3) // no need regist Span(3), default is 3
            SHADOW_WTC_FLAGS_[sPath + sKey] = iFlag;
          if (props['isPre.']) SHADOW_WTC_ISPRE_[sPath + sKey] = true;
        } else scanOneLevel(value, sPath + sKey + '.'); // scan sub-level
      });
    }
  }
docs: used only in __design__