Being used to JavaScript being flexible and all, you’ll be surprised of what goes underneath the hood upon running a .js script: V8 — Google’s extremely high-performance engine for JavaScript inside Chrome and node.js. Actually, unlike your average interpreter for JavaScript, v8 compiles JavaScript into code that’s native to the executing machine. Its execution speed comes out very effective. In that regard, below is the technical blog on ‘how JavaScript executes internally in an engine called v8.
V8 is a Just-In-Time (JIT) compiler-based engine that’s built for speed and efficiency. It has the following components:
Now, let’s break down how JavaScript goes from source code to execution.
While you write JavaScript, V8 does not directly execute it. Instead, it first passes it through a parser that converts source code into an Abstract Syntax Tree (AST).
Instead of executing JavaScript line after line, V8 employs an Ignition interpreter that interprets AST into a bytecode representation. This procedure provides JavaScript execution as more efficient than direct interpretation.
While the bytecode from Ignition would suffice for fast execution, V8 further optimizes it to ensure high-performance code. Here is how it works through TurboFan:
Garbage Collection: Managing Memory Efficiently
JavaScript’s dynamic nature means objects are created and discarded frequently. V8’s garbage collector automatically cleans up unused memory through:
This process ensures memory is efficiently used, preventing memory leaks and slowdowns.
Understanding V8’s internals helps developers write more efficient JavaScript. From parsing to execution, the combination of Ignition, TurboFan, and garbage collection ensures high performance. Next time you run a JavaScript function, remember—it’s not just being executed; it’s being optimized for speed!
What aspect of V8 excites you the most?
Let’s discuss in the comments!
Happy Coding!!!
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Author : Ms. Arusha Kamate