code: function handleProperties(schema, properties, node, stack) {
      var name = handleTagName(schema, node.tagName, node, stack)
      var attrs = schema.attributes
      var props = properties || {}
      var result = {}
      var allowed
      var prop
      var value
  
      allowed = own.call(attrs, name) ? attrs[name] : []
      allowed = [].concat(allowed, attrs['*'])
  
      for (prop in props) {
          value = props[prop]
  
          if (
              allowed.indexOf(prop) === -1 &&
              !(data(prop) && allowed.indexOf('data*') !== -1)
          ) {
              continue
          }
  
          if (value && typeof value === 'object' && 'length' in value) {
              value = handlePropertyValues(schema, value, prop)
          } else {
              value = handlePropertyValue(schema, value, prop)
          }
  
          if (value !== null && value !== undefined) {
              result[prop] = value
          }
      }
  
      return result
  }
docs: /* Sanitize `properties`.