Functional options pattern in Go

functional-options.go

// Read about this code pattern at https://davidbacisin.com/writing/golang-options-pattern
package app

type Client struct {
	baseUrl          string
	baseClient       *http.Client
	disableRedirects bool
}

type Option func(*Client)

func New(opt ...Option) *Client {
	c := new(Client)
	for _, o := range opt {
		o(c)
	}

	// Set a default client if one was not provided
	if c.baseClient == nil {
		c.baseClient = http.DefaultClient
	}

	return c
}

func WithBaseUrl(url string) Option {
	return func(c *Client) {
		c.baseUrl = url
	}
}

func WithBaseClient(base *http.Client) Option {
	return func(c *Client) {
		c.baseClient = base
	}
}

func WithoutRedirects() Option {
	return func(c *Client) {
		c.disableRedirects = true
	}
}