Golang does not provide optional arguments. Thus, we need to be a little creative here. A Porsche has four fields that are configurable.
type Porsche struct {
Model string
Trim string
Color string
Wheels string
}
Let's create a function type that is basically a setter for Porsche. Along with it, we will create four setter factory, one for each field.
type Option func(*Porsche)
func Model(val string) Option {
return func(p *Porsche) {
p.Model = val
}
}
func Trim(val string) Option {
return func(p *Porsche) {
p.Trim = val
}
}
func Color(val string) Option {
return func(p *Porsche) {
p.Color = val
}
}
func Wheels(val string) Option {
return func(p *Porsche) {
p.Wheels = val
}
}
The constructor will use the setters to optionally set properties for Porsche.
func NewPorsche(setters ...Option) *Porsche {
// Default configuration
p := &Porsche{
Model: "911",
Trim: "Base",
Color: "GT Silver",
Wheels: "Carrera",
}
for _, setter := range setters {
setter(p)
}
return p
}
The expected usage will look like this.
func main() {
NewPorsche(Trim("Turbo S"), Color("Carmine Red"))
}
