Microsoft to open source key pieces of its 'Chakra' JavaScript engine

Microsoft will release the core components of its 'Chakra' JavaScript engine as open source in January 2016.
Written by Mary Jo Foley, Senior Contributing Editor

Microsoft plans to publish the core components of its "Chakra" JavaScript engine to GitHub under an MIT open source license in January 2016.


Company officials announced the plans, which had been rumored for the past few weeks, at the JSConf on December 5.

Chakra was the codename for the JavaScript engine that Microsoft built to power Internet Explorer 9 and which it has used in subsequent IE and Edge browser releases. I didn't realize until this until this week that the Chakra engine also is powering Cortana, Outlook.com, Azure DocumentDB and TypeScript. With Windows 10, Microsoft enabled Node.js to run with Chakra, enabling Node.js to work on Windows 10 IoT Core.

I asked Microsoft officials who they expected to use Chakra and for what types of applications and services.A spokesperson said: "We are still in the very early stages of these discussions, so we don't yet have a full picture of what other members of the community could use Chakra for. Scenarios could run the full spectrum of uses of a JS Engine, from hardware-specific optimizations that accrue to Microsoft Edge's performance on certain chipsets, to cloud-based solutions, to mobile gaming, and small footprint devices."

Microsoft's blog post announcing its plans also says that "In addition to the public, several organizations have already expressed interest in contributing to ChakraCore--among many others, we look forward to working with Intel, AMD, and NodeSource as we develop this community."

Microsoft officials have designated the pieces of Chakra that Microsoft will be open sourcing as "ChakraCore." Those elements include the JIT, garbage collector, parser, interpreter and various application programming interfaces. Microsoft's won't be opensourcing other pieces of Chakra, including the COM diagnostic APIs and the private bindings to the browser and the Universal Windows Platform.

Microsoft execs plan to share more about its initial priorities and guidance on how the community can contribute to the ChakraCore project starting in January. While the initial release of ChakraCore will be Windows-only, Microsoft is expecting it to go beyond Windows.

From today's blog post:

"ChakraCore is already designed to fit into any application stack that calls for a fast, scalable, and lightweight engine. We intend to make it even more versatile over time, both within and beyond the Windows ecosystem. While the initial January release will be Windows-only, we are committed to bringing ChakraCore to other platforms in the future. We'd invite developers to help us in this pursuit by letting us know which other platforms they'd like to see ChakraCore supported on to help us prioritize future investments, or even by helping port it to the platform of their choice."

While one major computer company claims to be leading the way in making open source a part of their development strategy, Microsoft has been open sourcing more of its development platform pieces, including big swaths of the .NET stack, over the past few years.

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