Node.js is a powerful and widely-used JavaScript runtime environment that allows developers to execute JavaScript code on the server side. It is built on the V8 JavaScript engine, which is the same engine that powers Google Chrome. Node.js uses an event-driven, non-blocking I/O model, making it efficient and suitable for building scalable network applications. Here’s a detailed explanation of how Node.js works:
1. V8 JavaScript Engine
Node.js runs on the V8 JavaScript engine, which compiles JavaScript into native machine code. This compilation happens at runtime, allowing for efficient execution of JavaScript code. V8 is designed to increase the performance of JavaScript execution, which is crucial for the server-side operations that Node.js handles[3][4][14].
2. Single-Threaded Event Loop
One of the core features of Node.js is its single-threaded event loop. Despite being single-threaded, Node.js can handle numerous concurrent connections efficiently. This is achieved through its event-driven architecture. The event loop is responsible for executing all I/O operations asynchronously. Instead of blocking the thread and waiting for I/O operations to complete, Node.js registers a callback and lets the event loop continue running[1][2][5][6][7][11][17].
3. Non-Blocking I/O
Node.js uses non-blocking I/O operations. When Node.js performs an I/O operation, such as reading from the network, accessing a database, or file system, it will not stop executing JavaScript code while the I/O operation is being performed. Instead, Node.js will start the operation and then, while the device or resource completes the operation, continue to run other JavaScript code[5][11][16].
4. Event Queue and Callbacks
Node.js handles asynchronous callbacks using an event queue. When an asynchronous operation is initiated, a callback is defined. Node.js continues with the execution of the rest of the program without waiting for the operation to complete. Once the operation is completed, the callback associated with that operation is added to the event queue. The event loop checks the event queue in a loop, and if there are any callbacks in it, it will dequeue and execute them[1][2][7][11].
5. The Role of libuv
The libuv library is used by Node.js to handle asynchronous I/O operations. It provides a mechanism to handle file system...
