code: func (domain *TypedDataDomain) Map() map[string]interface{} {
  	dataMap := map[string]interface{}{}
  
  	if domain.ChainId != nil {
  		dataMap["chainId"] = domain.ChainId
  	}
  
  	if len(domain.Name) > 0 {
  		dataMap["name"] = domain.Name
  	}
  
  	if len(domain.Version) > 0 {
  		dataMap["version"] = domain.Version
  	}
  
  	if len(domain.VerifyingContract) > 0 {
  		dataMap["verifyingContract"] = domain.VerifyingContract
  	}
  
  	if len(domain.Salt) > 0 {
  		dataMap["salt"] = domain.Salt
  	}
  	return dataMap
  }
docs: // Map is a helper function to generate a map version of the domain