go-go-valueobject's Introduction

Go Go Value Object!

Inspired by my interest in domain driven design and Nicolò Pignatell's value object library for PHP I wanted to see if value objects could be implemented in Golang. Currently this is very much WIP with only two value objects: 1) a roman numeral 2) email address

Installation

go get github.com/codeinabox/go-go-valueobject

Usage

	import (
		"fmt"
		"github.com/codeinabox/go-go-valueobject"
	)

	func main() {
		email, err := valueobject.NewEmailAddress("[email protected]")
		fmt.Println(email.String())

		differentEmail, err := valueobject.NewEmailAddress("[email protected]")
		if email.Equals(differentEmail) == false {
			fmt.Println("As expected the two emails are different")
		}
	}

Implementing your own value object

Implementing your own value object is easy, it just needs to adhere to the Value interface eg

	import (
		"github.com/codeinabox/go-go-valueobject"
	)

	type Identifier struct {
		value string
	}

	func NewIdentifier(value string) (Identifier, error) {
		var n Identifier
		n.value = value
		return n, nil
	}

	func (n Identifier) String() string {
		return n.value
	}

	func (n Identifier) Equals(value valueobject.Value) bool {
		otherIdentifier, ok := value.(Identifier)
		return ok && n.value == otherIdentifier.value
	}