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Microsoft’s Chakra JavaScript Engine becomes open source

Scarlett Winter
A airplane turbine detail image via Shutterstock

Microsoft has made the core components of the Chakra JavaScript engine available as open source. The ChakraCore project also includes all the key elements of the JavaScript engine of Microsoft Edge, the new web browser by Microsoft. The software company already announced the step towards the end of last year at the JSConf Conference and the corresponding repository is now officially available on GitHub under the MIT license.

Microsoft had already developed a new JavaScript engine in 2008 under the codename Chakra which finally was first implemented in Internet Explorer 9 in 2011. The newest version of Chakra is not only in the Edge browser, but also supports Universal Windows 10 Apps like Cortana and, TypeScript and Node.js for Windows 10 IoT Core. With the publication of ChakraCore, the development of the engine should now be further expedited and made transparent.


ChakraCore shares the same resources which Chakra supports in Microsoft Edge. Chakra and ChakraCore do however differ on two points: ChakraCore does not expose Chakra’s private bindings to the browser nor the Universal Windows platform. Moreover, instead of the Component Object Model based diagnostic API, new platform-independent diagnostic APIs will be used which could be standardized in the future if need be.

Currently, ChakraCore supports Windows only; in the future support should be expanded to additional platforms such as Linux. Gaurav Seth (Principal PM Manager, Chakra) says the following in this regard in the Windows-Blog:

As a first step towards this goal, we have cleanly separated out Chakra’s JIT compiler, producing a build configuration that builds just the interpreter and runtime. This smaller build target is what we will initially enable cross platform porting.

Of course, the Community is also encouraged to provide feedback as to which additional platforms the JavaScript engine should be used on.

Roadmap should inform about planned targets

As Seth writes, a Roadmap should be published soon which will keep those interested about the current stage of development up to date and additionally provide a brief outlook on the planned changes and features over the next six months. The ChakraCore team’s to-do list includes among other things, the improvement of diagnostic support for ChakraCore and the promotion of Time Travel Debugging. The latter is to provide developers the possibility to go back in time and jump back and forth between callbacks when debugging JavaScript code. In addition, support of the ECMAScript 2015 (aka ES6) should be expanded.

To make initial headway very soon, Microsoft hopes for an active Community. The ChakraCore-Team accepts feedback via Twitter @ChakraCore and in the ChakaraCore-Repository on GitHub. For further information on the engine, reviewing the following video is highly recommended:

Scarlett Winter
Scarlett Winter studied book sciences and philosophy in Mainz, and works at S&S Media since November 2014.

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