[NODE JS] Worker Threads

When a Node.js process is launched, it runs:

One process
One thread
One event loop
One JS Engine Instance
One Node.js Instance
One process: a process is a global object that can be accessed anywhere and has information about what’s being executed at a time.

One thread: being single-threaded means that only one set of instructions is executed at a time in a given process.

One event loop: this is one of the most important aspects to understand about Node. It’s what allows Node to be asynchronous and have non-blocking I/O, — despite the fact that JavaScript is single-threaded — by offloading operations to the system kernel whenever possible through callbacks, promises and async/await.

One JS Engine Instance: this is a computer program that executes JavaScript code.

One Node.js Instance: the computer program that executes Node.js code.

The best solution:
The best solution for CPU performance is Worker Threads. Browsers have had the concept of Workers for a long time.

Instead of having:
One process
One thread
One event loop
One JS Engine Instance
One Node.js Instance

Worker threads have:
One process
Multiple threads
One event loop per thread
One JS Engine Instance per thread
One Node.js Instance per thread

[worker-diagram](https://images.ctfassets.net/hspc7zpa5cvq/20h5efXHT4bQbuf44mdq2H/a40944191d031217a9169b17a8ef35d6/worker-diagram_2x__1_.jpg)