functional options (pattern)

gistfile1.txt

package main

import "fmt"

type UserProfile struct {
	username  string
	email     string
	age       int
	avatarURL string
}

type ProfileOption func(profile *UserProfile) error

func Username(name string) ProfileOption {
	return func(profile *UserProfile) error {
		//some valiadtion can apply
		profile.username = name
		return nil
	}
}

func Email(e string) ProfileOption {
	return func(profile *UserProfile) error {
		//some valiadtion can apply
		profile.email = e
		return nil
	}
}

func Age(a int) ProfileOption {
	return func(profile *UserProfile) error {
		//some valiadtion can apply
		profile.age = a
		return nil
	}
}

func avatarURL(avatar string) ProfileOption {
	return func(profile *UserProfile) error {
		//some valiadtion can apply
		profile.avatarURL = avatar
		return nil
	}
}

func NewUserProfile(opts ...ProfileOption) (*UserProfile, error) {
	profile := &UserProfile{}
	for _, opt := range opts {
		err := opt(profile)
		if err != nil {
			return nil, err
		}
	}
	return profile, nil
}

func main() {
	// eg
	user, err := NewUserProfile(Username("bob"), Email("bob@gmail.com"), avatarURL("http://example.com/1.jpeg"))
	if err != nil {

	}
	fmt.Println(user)
}