Comparison of JSON encoding libraries for Arduino

aJson.ino

#include <aJSON.h>
  
void setup()
{
    Serial.begin(9600);
    
    char sensor[] = "outdoor";
    float value = 25.6;
    
    Serial.println(sensor);
    Serial.println(value);
    
    aJsonObject *root;
    root=aJson.createObject();  
    aJson.addStringToObject(root, "sensor", sensor);
    aJson.addNumberToObject(root, "value", value);
    
    char* string = aJson.print(root);
    Serial.println(string);
    
    free(string);
    aJson.deleteItem(root);
}
 
void loop()
{
 
}

ArduinoJson2.ino

#include <JsonGenerator.h>
 
using namespace ArduinoJson::Generator;
 
void setup()
{
    Serial.begin(9600);
    
    char sensor[] = "outdoor";
    float value = 25.6;
    
    Serial.println(sensor);
    Serial.println(value);
 
    JsonHashTable<2> hashTable;
    hashTable.add("sensor", sensor);
    hashTable.add("value", value);
    
    Serial.println(hashTable);
}
 
void loop()
{
 
}

ArduinoJson3.ino

#include <JsonGenerator.h>
 
using namespace ArduinoJson::Generator;
 
void setup()
{
    Serial.begin(9600);
    
    char sensor[] = "outdoor";
    float value = 25.6;
    
    Serial.println(sensor);
    Serial.println(value);
 
    JsonObject<2> object;
    object["sensor"] = sensor;
    object["value"] = value;
    
    Serial.println(object);
}
 
void loop()
{
 
}

None.ino

void setup()
{
    Serial.begin(9600);
    
    char sensor[] = "outdoor";
    float value = 25.6;
    
    Serial.println(sensor);
    Serial.println(value);
 
    Serial.println("{\"sensor\":\"outdoor\",\"value\":25.6}");
}
 
void loop()
{
 
}