code: function h(node, tagName, props, children) {
      if (
        (children === undefined || children === null) &&
        typeof props === 'object' &&
        'length' in props
      ) {
        children = props
        props = {}
      }
  
      return augment(node, {
        type: 'element',
        tagName: tagName,
        properties: props || {},
        children: children || []
      })
    }
docs: Create an element for a `node`.