code: function detectHeadingLevel(node, hostConfig) {
      var fontWeight = node && node.style.fontWeight;
      var fontSize = node && node.style.fontSize;
      if (fontSize === `${hostConfig.fontSizes.extraLarge}px`  && 
          fontWeight == hostConfig.fontWeights.bolder) {
          return 1;
      }
      if (fontSize === `${hostConfig.fontSizes.large}px` && 
          fontWeight == hostConfig.fontWeights.bolder) {
          return 2;
      }
      if (fontSize === `${hostConfig.fontSizes.medium}px` && 
          fontWeight == hostConfig.fontWeights.bolder) {
          return 3;
      }
      if (fontSize === `${hostConfig.fontSizes.medium}px` && 
          fontWeight == hostConfig.fontWeights.default) {
          return 4;
      }
      if (fontSize === `${hostConfig.fontSizes.default}px` && 
          fontWeight == hostConfig.fontWeights.bolder) {
          return 5;
      }
      if (fontSize === `${hostConfig.fontSizes.small}px` && 
          fontWeight == hostConfig.fontWeights.bolder) {
          return 6;
      }
      return null;
  }
docs: /*
  This currently must stay in sync with the adaptiveCardHelper.createHeadingTextBlock construction