ArduinoJson 6.15.2: JsonObject does not name a type

Question

Looking for some advice, I'm trying to work with the ArduinoJson library. The problem is with the code listed below:

#include <ArduinoJson.h>

const size_t capacity = JSON_ARRAY_SIZE(3) + JSON_OBJECT_SIZE(1) + 3*JSON_OBJECT_SIZE(2) + JSON_OBJECT_SIZE(6);
DynamicJsonDocument data(capacity);

JsonObject root = data.to<JsonObject>();
JsonArray sensors = root.createNestedArray("sensors");
JsonObject sensors_0  = sensors.createNestedObject();
sensors_0["type"] = "co2";
sensors_0["value"] = 400;

JsonObject  gps_obj = sensors.createNestedObject();
JsonObject gps_value_obj = gps_obj.createNestedObject("value");

void setup() {
  Serial.begin(115200);
  serializeJson(data, Serial);
}

void loop() {
  // not used
}

The error:

'sensors_0' does not name a type

This follows the documentation code at https://arduinojson.org/v6/api/jsonobject/createnestedobject/

Things I've tried:

1. Tried code directly from the documentation above (get the same error)
2. Checked the library folder for directory structure repetition.
3. If I remove the error lines (sensors_0["type"] = "co2" and sensors_0["value"] = 400) I get the exact JSON structure I desire without the keys:

{"sensors":[{},{"value":{}}]}

What might I be doing wrong?

Answer 1

Move below to setup() function sensors_0["type"] = "co2"; sensors_0["value"] = 400;