This is a really interesting pattern to initialize and configure a struct.
Given an app configuration
type App struct {
name string
port int
addr string
}
We can have:
package main
import "fmt"
type App struct {
name string
port int
addr string
}
type Option func(*App)
func New(opts ...Option) *App {
app := &App{
name: "Default Name",
port: 5000,
addr: "localhost",
}
for _, opt := range opts {
opt(app)
}
return app
}
func WithPort(port int) func(*App) {
return func(app *App) {
app.port = port
}
}
func WithName(name string) func(*App) {
return func(app *App) {
app.name = name
}
}
func WithAddr(addr string) func(*App) {
return func(app *App) {
app.addr = addr
}
}
func main() {
app := New(
WithName("Another name"),
WithPort(8080),
WithAddr("0.0.0.0"),
)
fmt.Println(app)
}
Can be tested here https://play.golang.org/p/ljnx3KQ0tVk