# Entity

Have an id (preferably a GUID rather than a DB generated int because business transactions do not rely on persistence, can be persisted after other operations carried out in model's behavior)

```typescript
import { 
  BaseDomainEntity, 
  Entity, 
  UniqueEntityID, 
  Result
} from 'types-ddd';

interface CarProps extends BaseDomainEntity {
  year: CarYearValueObject;
  color: CarColorValueObject;
}

class Car extends Entity<CarProps> {
  private constructor(props: CarProps) {
    super (props, Car.name)
  }
  
  get year (): CarYearValueObject {
    return this.props.year;
  }
  
  setYear (year: number): void {
    this.props.year = year;
  }
  
  get color (): CarColorValueObject {
    return this.props.color;
  }
  
  setColor (color: CarColorValueObject): void {
    this.props.color = color;
  }
  
  public static isValidYear (year: number): boolean {
    return year > 1920;
  }
  
  public static create (props: CarProps): Result<Car> {
   
    // Business logic validation. Just for example!
    // Some rules should be validated on the value object
    
    if (!Car.isValidYear(props.year.value)) {
        return Result.fail<Car>('Invalid year for a car');
     }
     
    return Result.ok<Car>(new Car(props));
  }
}

const car = Car.create({ ... }).getResult();

```

```
Accessible attributes for car
> car.color
> car.createdAt
> car.deletedAt
> car.equals
> car.id
> car.isDeleted
> car.isValidYear
> car.updatedAt
> car.year
> car.getHashCode
> car.toObject
```


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