The Magical World of JavaScript Engines: Everything you Need to Know
Tags: javascript, webdev, v8, engine
Published: 2023-05-06 20:26:10

JavaScript engines are the powerhouse of the JavaScript programming language. These engines are responsible for making JavaScript code run fast and smooth, giving the language its superpowers. In this article, we will explore the history of JavaScript engines, how they work, and some of the most popular engines available today. 💪🔥

## The Beginning of JavaScript Engines

Brandon Eich created the JavaScript language in just 10 days under the code name Moksha for Netscape Navigator in 1995. The first JavaScript engine was called SpiderMonkey 🕷️, and it was also created by Eich. This engine reads JavaScript code and executes it on a computer, giving developers the power they need to create dynamic and interactive web pages.

![Brandon Eich](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/zcepjl08bcxq3kpyc3em.png)

## Introduction of Google's V8 Engine

In 2006, Google introduced a game-changing engine called V8 ⚙️, written in C++. This engine was designed to be an optimising compiler and interpreter for JavaScript. It was hidden within the Chromium browser and led to the development of Node and Dino 🦖, which allowed developers to harness the full potential of JavaScript. The V8 engine was instrumental in revolutionising the JavaScript world by bringing a just-in-time compiler and interpreter to the language.

## How Do JavaScript Engines Work?

![JS Engine Internals](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/iu6gwyoxw4pzqvgqatdl.png)

JavaScript code is passed through the engine and converted into an abstract syntax tree. This abstract syntax tree can be executed through the Ignition interpreter or the top of an optimising compiler. The Ignition interpreter converts the code line by line into byte-code, while the top of an optimising compiler converts the entire code into an optimising machine code, which is then reused by the interpreter for better performance. This process makes it possible for engines like V8 to execute JavaScript at lightning-fast speeds.

## Popular JavaScript Engines Available Today

Today, there are many popular JavaScript engines available, each with its own strengths and weaknesses. Some of the most popular engines include SMP8, which is known for its fast startup times and low memory usage on Apple devices. Another newer runtime called Deno is written in the physics programming language, making it not only a runtime but also a transpiler and bundler with TypeScript support out of the box.

Other JavaScript engines for specific purposes include Boa, Quickjs, Jerry script, Duct tape, Rhino, Goja, and many more. Google's V8 engine is still at the forefront of most browser engines, and it continues to push the boundaries of JavaScript performance.

![JS Engines History](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/3k26ri622b1yz9t1kba5.png)

## The Bottom Line

In conclusion, the world of JavaScript engines is vast, with many players and opinions for different purposes. The magic of JavaScript engine lies in the execution of the code through an Ignition interpreter or turbofan optimising compiler like V8. JavaScript developers today have a wide variety of engines to choose from, each with its unique strengths and weaknesses. Understanding these engines and how they work is essential for any developer looking to push the boundaries of JavaScript's capabilities.

{% embed https://youtu.be/7ISPu5t40M0 %}

---

If you liked this post, please share it with your friends and fellow developers. And don’t forget to follow us for more programming tutorials and examples! 😊

And also,
have a look👀 @ my [Portfolio](https://dub.sh/raja-portfolio)
code👨‍💻 together @ [Github](https://dub.sh/raja-github)
connect🔗 @ [LinkedIn](https://dub.sh/raja-linkedin)