Create or assign a JsonDocument from a JsonArray/JsonObject/JsonVariant

src/ArduinoJson/Document/JsonDocument.hpp

@@ -5,6 +5,7 @@
 #pragma once
 
 #include "../Memory/MemoryPool.hpp"
+#include "../Object/ObjectRef.hpp"
 #include "../Variant/VariantRef.hpp"
 #include "../Variant/VariantTo.hpp"
 
@@ -53,6 +54,16 @@ class JsonDocument : public Visitable {
     return _pool.capacity();
   }
 
+  bool set(const JsonDocument& src) {
+    return to<VariantRef>().set(src.as<VariantRef>());
+  }
+
+  template <typename T>
+  typename enable_if<!is_base_of<JsonDocument, T>::value, bool>::type set(
+      const T& src) {
+    return to<VariantRef>().set(src);
+  }
+
   template <typename T>
   typename VariantTo<T>::type to() {
     clear();