example.ts

// Raw JSON types

interface CameraRaw {
  _id: string;
  name: string;
}

interface AccountRaw {
  _id: string;
  email: string;
  password: string;
  cameras: [CameraRaw]
}

// Domain objects

class Account {
  _id: MongoId;
  email: Email;
  password: Password;
  cameras: Array<Camera>

  private constructor(accountRaw: AccountRaw) {
    this._id = new MongoId(accountRaw._id);
    this.password = new Password(accountRaw.password);
    this.cameras = accountRaw.cameras.map(function(cameraRaw) {
      return new Camera(cameraRaw)
    })
  }
  
  // new code
  
  public fromRaw(accountRaw: AccountRaw): Either<Account, ValidationError> {
    var validation = AccountValidator(accountRaw, version = 3)
    if (validaton.isValid()) {
      return Left(new Account(accountRaw))
    } else {
      return Right(validation.error) // or some shit i dunno
    }
  }
  
}

class MongoId {
  value: string;

  constructor(value: string) {
    this.value = value;
  }
}

class Email {
  value: string;

  constructor(value: string) {
    this.value = value;
  }
}

class Password {
  value: string;

  constructor(value: string) {
    this.value = value;
  }
}

class Camera {
  _id: MongoId;
  name: String;

  constructor(cameraRaw: CameraRaw) {
    this._id = new MongoId(cameraRaw._id);
    this.name = cameraRaw.name;
  }
}


// Mongo mappers (ignore name - not sure what to call it)

interface MongoMapper<T> {
  findOne(value: T): Option<T>
  update(value: T): WriteResult<T>
  delete(value: T): WriteResult<T>
}

class AccountMongoMapper implements MongoMapper<Account> {
  findOne(account: Account): Option<T> {
    // find from DB where _id === account._id.value
  }

  update(account: Account): WriteResult<T> {
    // update account in DB
  }

  delete(account: Account): WriteResult<T> {
    // delete account in DB
  }
}