The Node.js Environment

Node.js has an event-driven architecture that is capable of processing requests asynchronously. Node.js has a single-threaded architecture. Traditional servers had multi-threaded architectures and they spawned a new thread as soon as a new request landed, but Node.js handles everything on a single thread. You may wonder how a single-threaded Node.js handles millions of requests. Well, the answer is the event loop. JavaScript works on a single thread and handles async operations thanks to its event-loop architecture. Any request that is taking a long time is sent to the background and the next request is addressed and processed. Before proceeding, let's understand the difference between synchronous and asynchronous processing.

Sync versus Async

If the execution of a program takes place in a linear sequence, it is synchronous processing. For example, in the following code block, an entire line will be read and executed before the process moves to the...