Chakra (JavaScript engine)

Chakra (JavaScript engine)
Name	Chakra
Developer	Microsoft
Released	12 January 2016
Latest release version	1.11.24
Latest release date	12 November 2019
Programming language	C++
Operating system	Microsoft Windows, macOS, Linux
Genre	JavaScript engine
License	MIT License

Chakra (JavaScript engine). Chakra is a JavaScript engine developed by Microsoft for its Internet Explorer and Microsoft Edge web browsers. It is a core component responsible for executing JavaScript code, implementing the ECMAScript standard, and enabling dynamic web applications. The engine was open-sourced as **ChakraCore** in 2016, allowing it to be integrated into projects beyond the Microsoft ecosystem.

Overview

Chakra was designed as a high-performance, JIT-compiling engine to power modern web experiences in Microsoft's browsers. It features a multi-tiered architecture that includes an interpreter, a simple JIT compiler, and a full optimizing compiler to balance fast startup and peak performance. The engine supports the evolving ECMAScript 2015 specification and subsequent standards, ensuring compatibility with major web platforms like Google Chrome and Mozilla Firefox. Its development was closely tied to the Windows 10 operating system and the now-discontinued Microsoft Edge (EdgeHTML) browser.

History

Development of Chakra began at Microsoft for Internet Explorer 9, released in 2011, where it introduced a new JIT compiler to compete with engines like V8 in Google Chrome. Significant updates continued through Internet Explorer 11 and the launch of the Microsoft Edge browser with Windows 10 in 2015. In a major strategic shift, Microsoft open-sourced the core components as **ChakraCore** in January 2016 under the MIT License. This move facilitated its use in non-browser contexts, such as server-side applications and other embedded systems. The engine's active development for Microsoft's browsers effectively ended when the company announced the transition of Microsoft Edge to the Chromium project, adopting the Blink and V8 engines instead.

Architecture

The architecture of Chakra is built around a multi-tiered execution pipeline to optimize for both quick code execution and long-running performance. It starts with a fast interpreter for initial parsing, followed by a simple JIT compiler (the "SimpleJIT") for warmer code. The most frequently executed functions are promoted to the high-throughput optimizing compiler (the "FullJIT"), which performs advanced techniques like type specialization and inline caching. The engine includes a precise, generational garbage collector for efficient memory management. ChakraCore also exposed a powerful C++ API and supported JavaScript Runtime (JSRT) hosting, enabling integration with projects like Node.js through the now-archived Node-ChakraCore fork.

Features

Key features of the Chakra engine included full support for ECMAScript 2016 and many proposals from TC39, the committee that standardizes ECMAScript. It implemented advanced JavaScript optimizations such as profile-guided optimization, lazy parsing, and background JIT compilation to improve page load times. The engine supported asm.js and was an early implementer of the WebAssembly specification, allowing near-native performance for compute-intensive tasks. For diagnostics, it provided extensive profiling and debugging capabilities through the ETW framework on Windows and tools like the ChakraCore Diagnostics API.

Usage

The primary historical usage of Chakra was within Microsoft's web browsers, namely Internet Explorer 9 through Internet Explorer 11 and the original Microsoft Edge (EdgeHTML). Following its open-sourcing, ChakraCore was adopted for various non-browser applications, including server-side scripting and game engines. It powered the experimental Node-ChakraCore runtime, an official fork of Node.js that aimed to offer enhanced diagnostics and Windows integration. The engine was also integrated into certain Universal Windows Platform apps and used within projects like React Native for Windows by Microsoft.

Development and forks

Active development of Chakra was led by Microsoft engineers, with the codebase hosted publicly on GitHub after 2016. The main fork, **ChakraCore**, served as the foundation for community experimentation and embedding into third-party software. A significant derivative was the aforementioned Node-ChakraCore project, initiated by Microsoft in collaboration with the Node.js foundation. Other community efforts explored its use in game development environments and alternative JavaScript runtimes. Development of new features for ChakraCore has largely ceased since Microsoft's browser strategy shifted to Chromium, though the project remains available as open-source software.

Category:JavaScript engines Category:Microsoft software Category:Free software programmed in C++