text: const exp = module.exports = {}
  
  const FIELDS = [ "head", "body", "updatedBy", "updatedAt" ]
  
  exp.Header = class {
  
      formatForDb() {
          const res = {}
          FIELDS.forEach(f => res[f] = this[f])
          return res
      }
  
      parseFromDb(dbHeader) {
          FIELDS.forEach(f => this[f] = dbHeader[f])
      }
  
      static newFromDb(dbHeader) {
          const header = new this()
          if (dbHeader) header.parseFromDb(dbHeader)
          return header
      }
  }