See ArduinoJson memory usage and speed with string deduplication

StringDeduplicationDemo.ino

#include <ArduinoJson.h>

void setup() {
  
  Serial.begin(9600);
  while (!Serial) continue;
  
  StaticJsonDocument<516> doc;

  const char* json = R"({"list":[{"temperature":21.2,"humidity":68.9,"weather":"overcast clouds"},{"temperature":19.7,"humidity":62.1,"weather":"clear sky"},{"temperature":18.6,"humidity":59.8,"weather":"clear sky"}]})";

  unsigned long start = micros();
  DeserializationError error = deserializeJson(doc, json);
  unsigned long stop = micros();

  // Test if parsing succeeds.
  if (error) {
    Serial.print(F("deserializeJson() failed: "));
    Serial.println(error.c_str());
    return;
  }


  Serial.print("doc.memoryUsage() = ");
  Serial.println(doc.memoryUsage());
  
  Serial.print("duration = ");
  Serial.print(stop-start);
  Serial.println("µs");
}

void loop() {
  // not used in this example
}