尝试将结构映射到我公开的API结构

Question

I am writing mapping functions that map my internal models to those that I will expose in my API.

How do I map the Locations property. Do I range over them? Do I have to init the UserApi locations first?

I little confused on how to best do this without having any nil exceptions etc.

func mapUserToApi(user User) UserApi {
  api := &UserApi{
     Id: user.Id,
     ..
     ..
  }

  for index, location := range user.Locations {
    /// ????????????
  }

  return api
}

func mapLocationToApi(location Locatio) LocationApi {
  ..
}


type User struct {
  Id int

  Locations []Location
}

type UserApi struct {
  Id int

  Locations []LocationApi
}

Answer 1

Allocate first then loop for range

func mapUserToApi(user User) UserApi {
  api := &UserApi{
     Id: user.Id,
     Locations: make([]LocationApi, len(user.Locations), len(user.Locations)),
  }

  for index, location := range user.Locations {
    api.Locations[index] = mapLocationToApi(location)
  }

  return api
}