Callbacks

Callbacks are functions passed as arguments to other functions, which are then invoked (or 'called back') at a later time, typically after an asynchronous operation completes or an event occurs. They are a fundamental pattern in programming, especially in JavaScript and other event-driven languages, for handling non-blocking operations like I/O, timers, or user interactions. This pattern enables code to execute in response to specific conditions without halting the main program flow.

Also known as: Callback functions, Callback pattern, Asynchronous callbacks, Event handlers, CB

Why learn Callbacks?

Developers should learn callbacks to manage asynchronous tasks effectively, such as handling API responses, file operations, or UI events in web development. They are essential in environments where blocking operations would degrade performance, like in Node.js for server-side applications or in browser-based JavaScript for responsive user interfaces. However, overuse can lead to 'callback hell' (deeply nested code), so understanding them is a stepping stone to more advanced patterns like promises or async/await.

Learning Resources

• docs: MDN Web Docs: Callback function
• tutorial: JavaScript.info: Callbacks
• tutorial: Node.js Callback Pattern Tutorial
• tutorial: FreeCodeCamp: Callbacks in JavaScript
• video: YouTube: JavaScript Callbacks Explained