Head Elements Sorting

[Kostya1]

I need to make a json from iarray. I'm doing it like you in your example

json j;

j["pi"] = 3.141;

j["happy"] = true;

So, result json in this example will be:

{
"happy": true,
"pi": 3.141
}

The keys are sorted alphabetically. But I need
But I want make json like this

{
"pi": 3.141,
"happy": true
}

How can I make the keys in the same order as I add them?

[nlohmann]

This is not directly possible.

From the README:

By default, the library does not preserve the insertion order of object elements. This is standards-compliant, as the JSON standard defines objects as "an unordered collection of zero or more name/value pairs". If you do want to preserve the insertion order, you can specialize the object type with containers like tsl::ordered_map or nlohmann::fifo_map.

[nlohmann]

To be fixed with #2258.