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ValueObject

Definition​

Value Objects are objects that have no conceptual identity and describe some characteristics of a thing. They are defined only by their properties and their equality is not based on identity.

Examples​

Declaring a ValueObject​
ValueObject TitleVO {
  constructor(props: TitleProps): (OK(TitleVO), Errors(DomainErrors.TitleOutOfBoundsError)) {
    applyRules(TitleOutOfBoundsRule(props.title));
  }
}
Using a ValueObject​
const title = TitleVO({ title: requestDTO.title });

Syntax​

Declaring a Value Object​
ValueObject <identifier name with a VO suffix> {

  //constant variable declarations
  const <identifier> : <type> = <expression>;

  // constructor declaration, here we define whatever needs specific handling during the creation of the value object and
  //we use applyRules to ensure its validation. By default automatic getters are generated.
  constructor(<props of the ValueObject>) : (OK(<type>), Errors(<DomainErrorIdentifier> '|' <DomainErrorIdentifier>...)) {
    <statements>
  }

  // private method declaration
  <[optional] private> <method identifier> (<arg, arg...>): <type> {
    <statements>
  }

}
Creating a Value Object​
<name of Value Object>(<props>);

References for the above:

Further reading​