What is an Event Loop?

In Node.js, the event loop is the mechanism that handles the execution of JavaScript code. It is the core of the Node.js runtime and is responsible for scheduling asynchronous operations, such as I/O operations and timers.

The event loop works by continuously monitoring a queue of callback functions that are waiting to be executed. When an event occurs that triggers one of these callback functions, the event loop pushes the callback onto the call stack and executes it. Once the callback has finished executing, the event loop continues to process the next callback in the queue.

This process continues until there are no more callbacks left to be executed, at which point the event loop enters a "waiting" state, waiting for new events to occur. This allows Node.js to perform non-blocking I/O operations and to handle many concurrent connections with a small number of threads.