Explain V8 engine in Node.js - GeeksforGeeks (2024)

What is a V8 Engine?

V8 is a C++-based open-source JavaScript engine developed by Google. It was originally designed for Google Chrome and Chromium-based browsers (such as Brave) in 2008, but it was later utilized to create Node.js for server-side coding. In reality, JSON-based No-SQL databases like Couchbase and the widely used MongoDB use the V8 engine. V8 also powers Electron, a prominent desktop application framework, and Demo, the latest server-side runtime environment.

V8 is known to be a JavaScript engine because it takes JavaScript code and executes it while browsing in Chrome. It provides a runtime environment for the execution of JavaScript code. The best part is that the JavaScript engine is completely independent of the browser in which it runs. This is the feature that led Node.js designers to choose the V8 engine to power the framework, and the rest is history. The V8 engine was also utilized to construct desktop frameworks and databases as Node.JS grew in popularity.

How does the V8 Engine works?

A JavaScript Engine is an interpreter that interprets JavaScript code and runs it. The first way to develop a JavaScript engine is to implement it as a standard interpreter, as done by Mozilla’s SpiderMonkey. The other option is to employ Just-in-Time (JIT) compilation, which turns native JavaScript code to machine code as V8 does. The distinction between V8 code and other programming languages is that it does not generate intermediate code.

The Ignition interpreter compiles JavaScript code and generates non-optimized machine code when a developer or program runs it on V8 (i.e. in a browser or Node environment). The Turbofan and Crankshaft components of V8 examine and recompile the machine code at runtime for optimal performance.

Node.Js and V8

Node.js is referred to as a runtime environment since it contains everything you need to run a JavaScript program.

This V8 engine is at the heart of Node.js. The diagram compares the Java Virtual Machine (JVM), which is used to power the Java Runtime environment with the V8 engine. The Node.js runtime environment includes several Node APIs to power the Node.js environment in addition to the V8 engine. We can enhance the functionality of our node code by installing extra npm packages.

One thing to keep in mind is that V8 is essentially a standalone C++ library that is utilized to run JavaScript code by Node or Chromium. V8 exposes an API that other applications can utilize, so you can embed V8 in your C++ program and run a JavaScript program from it. Node and Chrome work in this manner.

Let’s say we want to add the ability to have statements like print(‘hello world’) in addition to console.log(‘Hello World’) in our JavaScript code. In V8, which is already open-sourced, we can add our own C++ implementation of the print function.

Memory limit of V8 in Node.js

Currently, V8 has a RAM limit of 512MB on 32-bit computers and 1GB on 64-bit platforms by default. This limit can be increased by setting –max-old-space-size to a maximum of ~1gb for 32-bit and ~1.7gb for 64-bit systems. If you’re running out of memory, it’s a good idea to break your single process into numerous workers.

Can Node.js work without V8?

V8 is required for the current Node.js engine to function. In the absence of V8, it wouldn’t have a JavaScript engine, and thus wouldn’t be able to run JavaScript code. The V8 interface between C++ and JavaScript is used by the native code bindings that come with Node.js, such as the fs (File System) module and the Net module.

Although anything is possible in the tech world, and Microsoft attempted in July 2016 to replace the V8 engine in Node.js with the Chakra JavaScript engine (which was used in Edge at the time), that project never took off, and Microsoft Edge recently switched to Chromium, which uses the V8 JavaScript engine.

DENO is the newest technology introduced in the domain of server-side programming. Many believe it will be a Node.js replacement in the next 2-3 years, and it is also powered by the V8 JavaScript engine.