Removed JsonValue::null(), moved the instance to JsonObjectBase

JsonGenerator/JsonObjectBase.cpp

@@ -9,6 +9,10 @@
 using namespace ArduinoJson::Generator;
 using namespace ArduinoJson::Internals;
 
+
+JsonValue JsonObjectBase::nullValue;
+
+
 size_t JsonObjectBase::printTo(Print& p) const
 {
     size_t n = 0;
@@ -51,10 +55,19 @@ JsonValue& JsonObjectBase::operator[](char const* key)
         p++;
     }
 
-    if (count >= capacity)        
-        return JsonValue::null();
-    
-    count++;
-    p->key = key;
-    return p->value;
+    JsonValue* value;
+
+    if (count < capacity)
+    {
+        count++;
+        p->key = key;
+        value = &p->value;
+    }
+    else
+    {
+        value = &nullValue;
+    }
+
+    value->reset();
+    return *value;
 }

JsonGenerator/JsonObjectBase.h

@@ -50,6 +50,8 @@ namespace ArduinoJson
         private:
             KeyValuePair* items;
             int capacity, count;
+
+            static JsonValue nullValue;
         };
     }
 }

JsonGenerator/JsonValue.cpp

@@ -9,8 +9,6 @@
 using namespace ArduinoJson::Generator;
 using namespace ArduinoJson::Internals;
 
-JsonValue JsonValue::nullInstance;
-
 size_t JsonValue::printBoolTo(const Content& c, Print& p)
 {
     return p.print(c.asBool ? "true" : "false");

JsonGenerator/JsonValue.h

@@ -100,9 +100,10 @@ namespace ArduinoJson
                 return printToImpl(content, p);
             }
 
-            static JsonValue& null()
+            void reset()
             {
-                return nullInstance;
+                content.asDouble = 0;
+                printToImpl = printStringTo;
             }
 
         private:
@@ -129,8 +130,6 @@ namespace ArduinoJson
             {
                 return p.print(c.asDouble, DIGITS);
             }
-
-            static JsonValue nullInstance;
         };
     }
 }

JsonGeneratorTests/JsonObject_Indexer_Tests.cpp

@@ -18,10 +18,10 @@ namespace JsonGeneratorTests
 
     public:
 
-    /*    TEST_METHOD(Empty)
+        TEST_METHOD(Empty)
         {
             mustNotContain("key");
-        }*/
+        }
 
         TEST_METHOD(OneString)
         {
@@ -35,8 +35,14 @@ namespace JsonGeneratorTests
 
         void mustContain(const char* key, const char* expected)
         {
-            auto actual = (const char*) object[key];
+            const char* actual = object[key];
             Assert::AreEqual(expected, actual);
         }
+
+        void mustNotContain(const char* key)
+        {
+            const char* actual = object[key];
+            Assert::IsNull(actual);
+        }
     };
 }