JavaScript

The language of the web, on the client, the server and the edge.

Paradigm

Multi-paradigm, prototype-based, functional

Typing

Dynamic, weak (TypeScript adds static types)

Memory

Garbage collected

Runs

V8 / SpiderMonkey / JSC engines (JIT)

Concurrency

Single-threaded event loop, workers

Performance

How JavaScript runs, and what that means in practice.

JIT-compiled by the engine (V8 in Node.js and Chrome) with inline caching and speculative optimisation.

Generational garbage collector; hidden classes reward objects with consistent shapes.

Single-threaded event loop excels at concurrent I/O; worker_threads / Web Workers for parallel CPU work.

Very good for I/O-bound services; CPU-bound work is slower than compiled languages and blocks the loop.

Saved in this browser only. Part of From code to production (0/5).