#include <iostream>
#include <vector>

#include <inja/inja.hpp>

int main()
{
   auto data = nlohmann::json();
   data["guests"] = std::vector{ "Jeff","Patrick","Tom" };
   data["numbers"] = std::vector{ 1,2,3 };

   std::cout << inja::render("{{ join(guests, \" - \") }}", data) << '\n';
   std::cout << inja::render("{{ join(numbers, \" | \") }}", data) << '\n';
}

Jeff - Patrick - Tom
1 | 2 | 3