ArduinoJson 6.18.0
📰 Read the complete article on arduinojson.org
Changes since 6.17.3
- Added support for custom converters (issue #687)
- Added support for
Printable
(issue #1444) - Removed support for
char
values, see below (issue #1498) deserializeJson()
leaves\uXXXX
unchanged instead of returningNotSupported
deserializeMsgPack()
insertsnull
instead of returningNotSupported
- Removed
DeserializationError::NotSupported
- Added
JsonVariant::is<JsonArrayConst/JsonObjectConst>()
(issue #1412) - Added
JsonVariant::is<JsonVariant/JsonVariantConst>()
(issue #1412) - Changed
JsonVariantConst::is<JsonArray/JsonObject>()
to returnfalse
(issue #1412) - Simplified
JsonVariant::as<T>()
to always returnT
(see below) - Updated folders list in
.mbedignore
(PR #1515 by @AGlass0fMilk) - Fixed member-call-on-null-pointer in
getMember()
when array is empty serializeMsgPack(doc, buffer, size)
doesn't add null-terminator anymore (issue #1545)serializeJson(doc, buffer, size)
adds null-terminator only if there is enough room- PlatformIO: set
build.libArchive
tofalse
(PR #1550 by @askreet)
BREAKING CHANGES
Support for
char
removedWe cannot cast a
JsonVariant
to achar
anymore, so the following will break:char age = doc["age"]; // error: no matching function for call to 'variantAs(VariantData*&)'Instead, you must use another integral type, such as
int8_t
:int8_t age = doc["age"]; // OKSimilarly, we cannot assign from a
char
anymore, so the following will break:char age; doc["age"] = age; // error: no matching function for call to 'VariantRef::set(const char&)'Instead, you must use another integral type, such as
int8_t
:int8_t age; doc["age"] = age; // OKA deprecation warning with the message "Support for
char
is deprecated, useint8_t
oruint8_t
instead" was added to allow a smooth transition.
as<T>()
always returnsT
Previously,
JsonVariant::as<T>()
could return a type different fromT
.
The most common example isas<char*>()
that returned aconst char*
.
While this feature simplified a few use cases, it was confusing and complicated the
implementation of custom converters.Starting from this version,
as<T>
doesn't try to auto-correct the return type and always returnT
,
which means that you cannot write this anymore:Serial.println(doc["sensor"].as<char*>()); // error: invalid conversion from 'const char*' to 'char*' [-fpermissive]Instead, you must write:
Serial.println(doc["sensor"].as<const char*>()); // OKA deprecation warning with the message "Replace
as<char*>()
withas<const char*>()
" was added to allow a smooth transition.
DeserializationError::NotSupported
removedOn a different topic,
DeserializationError::NotSupported
has been removed.
Instead of returning this error:
deserializeJson()
leaves\uXXXX
unchanged (only whenARDUINOJSON_DECODE_UNICODE
is0
)deserializeMsgPack()
replaces unsupported values withnull
sConst-aware
is<T>()
Lastly, a very minor change concerns
JsonVariantConst::is<T>()
.
It used to returntrue
forJsonArray
andJsonOject
, but now it returnsfalse
.
Instead, you must useJsonArrayConst
andJsonObjectConst
.
How to install
There are several ways to install ArduinoJson, from simpler to more complex:
- Use the Arduino Library Manager or equivalent
- Download
ArduinoJson-v6.18.0.h
put it in your project folder - Download
ArduinoJson-v6.18.0.zip
and extract it into yourlibraries
folder
Note: ArduinoJson-v6.18.0.h
and ArduinoJson-v6.18.0.hpp
are almost identical; the difference is that the .hpp
keeps everything in the ArduinoJson
namespace.