Profile & ProfileArgType

Profile.kt

data class Profile(val firstName:String, val lastName:String){
  override fun toString(): String = Uri.encode(Gson().toJson(this))
}

class ProfileArgType : JsonNavType<Profile>() {
    override fun fromJsonParse(value: String): Profile = Gson().fromJson(value, Profile::class.java)

    override fun FromProfileArguments.getJsonParse(): String = Gson().toJson(this)
}
//Discaimer : Gson or Moshi or any other library is up to you


NavHost(navController = navController, startDestination = "profile"){
    /*...*/
    composable(
      route="friendprofile/{profile}", 
      arguments = listOf(navArgument("profile"){
        type = ProfileArgType()
      })
    ) { navBackStackEntry->
      val profile = navBackStackEntry.arguments?.getString("profile")?.let { Gson().fromJson(it, Profile::class.java) }
      FriendProfile(navController, profile) 
    }
}