02 Architecture

1. JavaScript Runtime Environment (JS Runtime)

The JavaScript runtime environment is the software environment that allows JavaScript code to be executed

• Both in browsers and on server-side platforms like Node.js.
• JavaScript engine, which interprets and executes JavaScript code;
• The Web APIs, which provide access to browser features like the DOM and AJAX;
• and the event loop, which manages asynchronous code execution and callbacks.

2. JavaScript Engine

Javascript engine is the heart of the Javascript runtime environment.

• Every browser has their own implementation of the JS engine
• Google chrome uses the v8 engine, that's used in Node.js, deno etc.
  

References

• JS Architecture Namaste Java Script
• V8 Engine docs