Callback Function in JavaScript

• A callback function in javascript is a function passed as an arguement into another function and executed later.

• The benefit of using a callback function is that you can wait for the result of a previous function call and then execute another function call.

How Callbacks Work

• Passing the Function: The function you want to run after some operation is passed as an argument to another function.

• Executing the Callback: The main function executes the callback function at the appropriate time. This can be after a delay, once a task is complete, or when an event occurs.

Types of Callbacks:

1. Asynchronous Callbacks

• Asynchronous callbacks are executed at a later time, allowing the main program to continue running without waiting.

• This is essential for preventing the application from freezing during long-running tasks like network requests.

1. Synchronous Callbacks

• Synchronous Callbacks are executed immediately within the outer function, blocking further operations until completion.

• Array methods like map(), filter(), and forEach() use synchronous callbacks.

Example For Callback Function:

Avoid callbacks when:

• Code becomes nested and unreadable (use Promises or async/await).

• You need error handling in asynchronous operations (Promises are better).

References:

How to Use Callback Functions in JavaScript

When you're building dynamic applications with JavaScript that display real-time data – like a weather app or live sports dashboard – you'll need a way to automatically fetch new data from an external source without disrupting the user experience. Yo...

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JavaScript Callbacks - GeeksforGeeks

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