Store offset between slots to reduce memory usage

test/JsonArray/get.cpp

@@ -0,0 +1,16 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("JsonArray::get()") {
+  DynamicJsonDocument doc;
+  deserializeJson(doc, "[1,2,3]");
+  JsonArray array = doc.as<JsonArray>();
+
+  SECTION("Overflow") {
+    REQUIRE(array.get(3).isNull());
+  }
+}