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Emscripten vs Hermes: What are the differences?
Introduction
Emscripten and Hermes are both tools used in the world of web development, specifically for optimizing and improving the performance of JavaScript applications. However, there are several key differences between the two that set them apart in terms of functionality and use. In this article, we will explore these differences in detail.
Compilation Process: One of the major differences between Emscripten and Hermes lies in their compilation process. Emscripten utilizes LLVM (Low-Level Virtual Machine) to compile C and C++ code into JavaScript, allowing developers to run their native code directly in the browser. On the other hand, Hermes is a JavaScript engine designed specifically for mobile devices, focusing on improving runtime performance by utilizing ahead-of-time (AOT) compilation techniques. This means that Hermes compiles JavaScript code into highly optimized native code, resulting in faster execution on mobile platforms.
Compatibility: While Emscripten is compatible with a wide range of platforms, including browsers, Node.js, and even gaming consoles, Hermes is primarily designed for mobile platforms such as Android and iOS. Emscripten's ability to generate JavaScript code allows it to work in various environments, making it a versatile tool for web developers. However, Hermes' specialization in mobile platforms makes it a more efficient option for optimizing JavaScript performance specifically for mobile applications.
Execution Environment: Another significant difference between Emscripten and Hermes lies in their execution environments. Emscripten runs within the JavaScript runtime of a web browser or Node.js, and therefore relies on the underlying JavaScript engine to interpret and execute the generated code. In contrast, Hermes replaces the default JavaScript engine in mobile platforms, effectively becoming the runtime environment itself. This allows Hermes to have more control and optimization potential over the execution of JavaScript code, resulting in improved performance compared to a generic JavaScript engine.
Optimization Focus: While both Emscripten and Hermes aim to improve JavaScript performance, they prioritize different aspects of optimization. Emscripten primarily focuses on translating native code into portable and efficient JavaScript, allowing developers to run high-performance applications in the browser. In contrast, Hermes focuses on reducing memory usage and startup times for mobile applications, specifically targeting the limitations of mobile devices. This means that Hermes is optimized to provide a smooth and responsive user experience on resource-constrained mobile platforms.
Community and Support: Emscripten and Hermes have different levels of community and support. Emscripten has been around for a longer time and has a larger user base, resulting in a more active and vibrant community. This means that developers using Emscripten can benefit from a wealth of resources, documentation, and community-driven solutions. On the other hand, Hermes, being a relatively new tool, has a smaller community and may not have the same level of community support as Emscripten. However, being backed by Facebook, Hermes has the advantage of being developed and maintained by a renowned tech company, ensuring ongoing updates and improvements.
In Summary, Emscripten and Hermes differ in their compilation process, compatibility, execution environment, optimization focus, and community support. Emscripten utilizes LLVM for compiling native code into JavaScript, and it works across various platforms, while Hermes specializes in mobile platforms and focuses on improving runtime performance. Emscripten runs within existing JavaScript runtimes, while Hermes replaces the default JavaScript engine. Emscripten prioritizes portability and high-performance applications, while Hermes emphasizes memory usage and startup times. Emscripten has a larger community and more resources, whereas Hermes is backed by Facebook but has a smaller community.
