package main

import (
	"fmt"
	"reflect"

	"github.com/imdario/mergo"
)

type Foo struct {
	Ignore []string
	B      int64
}

func main() {
	src := Foo{
		Ignore: []string{"one", "two", "three"},
		B:      2,
	}
	dest := Foo{
		Ignore: []string{"one", "two", "four", "seven"},
	}

	mergo.Merge(&dest, src, mergo.WithTransformers(StringSliceTransformer{}))
	fmt.Println(dest)
	// Will print
	// {two 2}
}

type StringSliceTransformer struct {
}

// MergeStrings merges two strings
func (s StringSliceTransformer) Transformer(typ reflect.Type) func(dst, src reflect.Value) error {
	if typ == reflect.TypeOf([]string{}) {
		return func(dst, src reflect.Value) error {

		}
	}
}