The Callback Function

The video tutorial explores callback functions in Node.js, emphasizing their role in asynchronous programming. It covers practical examples using setTimeout and filter, and demonstrates creating custom functions that accept callbacks. The tutorial also simulates asynchronous processes and presents a challenge to reinforce learning by creating a function using the callback pattern.

Why are callback functions crucial in Node.js development?

• They allow synchronous execution of code.

• They are used only for error handling.

• They enable asynchronous operations.

• They simplify the code structure.

What is the primary purpose of a callback function?

• To handle errors in JavaScript.

• To replace the main function in a program.

• To be passed as an argument to another function for later execution.

• To execute immediately after being defined.

How does the filter method use the callback pattern?

• It uses the callback function to handle errors.

• It calls the callback function for each element in the array synchronously.

• It executes the callback function asynchronously.

• It does not use a callback function.

What is a key difference between setTimeout and filter regarding callbacks?

• Both setTimeout and filter are synchronous.

• setTimeout is asynchronous, while filter is synchronous.

• Both setTimeout and filter are asynchronous.

• setTimeout is synchronous, while filter is asynchronous.

Why might you define your own function to accept a callback?

• To simplify the function's logic.

• To avoid using built-in JavaScript functions.

• To handle asynchronous operations within the function.

• To make the function execute faster.

What problem does the callback pattern solve in asynchronous functions?

• It enables functions to execute synchronously.

• It eliminates the need for functions altogether.

• It provides a way to handle data once it's available.

• It allows functions to return values directly.

In the geocode example, why can't we use a return statement for asynchronous operations?

• Because return statements are only for synchronous functions.

• Because the return statement would cause an error.

• Because the return statement would execute before the asynchronous operation completes.

• Because return statements are not allowed in JavaScript.

What is the purpose of the callback function in the geocode example?

• To execute before the asynchronous operation starts.

• To handle the data once the asynchronous operation is complete.

• To replace the main function.

• To return the data immediately.

In the challenge, what is the role of the callback in the add function?

• To handle errors in the addition process.

• To execute after a delay with the calculated sum.

• To replace the addition operation.

• To return the sum immediately.

What is the expected output of the add function challenge after 2 seconds?

• The number 10

• No output

• The number 5

• An error message