Feature request: JsonString.as<T>()

[razvanphp]

Hey, thank you for your great work!

It would be a lot easier (and cleaner) if this functionality would be implemented 🙂

Currently, only the .value() has it as it is implemented in JsonVariant.

My code snippet:

for (JsonPair el : json.as<JsonObject>()) {
    Serial.println(atoi(el.key().c_str()));
    Serial.println(el.value().as<int>());
}

Cheers,
R

[bblanchon]

Hi @razvanphp,

key() is a string (a JsonString to be exact), why would you expect it to have the same interface as a variant?

Best regard,
Benoit

[razvanphp]

I do not expect that, I was just suggesting that this convenience method would serve in some cases when the key is actually of different type than string, avoiding extra operations like atoi.

[bblanchon]

So, you're asking for JsonString::as<int>(), right?

I must say that I'm not fond of this idea:

1. It blurs the message that JsonString is a string and not a JsonVariant.
2. It would work for double and bool as well, but I doubt anyone will ever use it.
3. It would not work for JsonArray and JsonObject even if the key contains a JSON array/object, and even if it worked, who would do that?

I'm sorry, but I'll need to see some very convincing code examples before adding something like that in the library.

[razvanphp]

Well, I was using it just for int, as you can see above in my code snippet, because I was setting registers in arduino and the key in json is not valid as integer, it needs to be string.

Indeed JsonString is a string representation, but one would still need to call c_str() to really use it as a string, why wouldn't it be another convenience method to convert to any other type?

Obviously It's your call and feel free to discard my suggestion 🙂