package main

import "log"
import "github.com/jinzhu/copier"

func main() {
        type Sample1 struct {
		Foobar *[]string
	}
	type Sample2 struct {
		Foobar []string
	}

	from := Sample1{}
	to := Sample2{}
	err := copier.CopyWithOption(&to, from, copier.Option{
		DeepCopy: true,
	})
	log.Printf("DeepCopy enabled, err: %v", err)
	
	err = copier.Copy(&to, from)
	log.Printf("DeepCopy disabled, err: %v", err)

	log.Printf("from: %v", from)
	log.Printf("to: %v", to)
}

Output:
2009/11/10 23:00:00 DeepCopy enabled, err: copy from is invalid
2009/11/10 23:00:00 DeepCopy disabled, err: <nil>
2009/11/10 23:00:00 from: {<nil>}
2009/11/10 23:00:00 to: {[]}