Contents
What is a Callback?
A callback is a function that is passed as an argument to another function and is executed at a later time. It is commonly used in asynchronous programming to handle the results of an asynchronous operation or to perform some action once an operation has completed. Callbacks allow us to write code that can be executed out of order, giving us more control over the flow of our programs.
How Function Calls Work in Asynchronous Processing
In asynchronous processing, function calls are not executed immediately. Instead, they are scheduled to run in the background while the main program continues to execute. This allows other tasks to be performed without waiting for a function call to complete.
When a function that supports asynchronous processing is called, it initiates an operation and then returns control back to the caller without waiting for the operation to finish. The caller can then continue executing other tasks while the operation is being processed.
Once the operation is complete, a callback function is invoked with the result of the operation. This callback function is often provided by the caller and specifies what should be done with the result. It allows the caller to define a custom logic to handle the asynchronous result.
Callbacks are essential in handling asynchronous operations because they allow us to define what should happen once the operation is finished. Without callbacks, our programs would have to wait for each operation to complete before moving on to the next step, which would result in slower and less efficient code.
One common use case of callbacks is in web development, where asynchronous operations like sending HTTP requests or accessing databases are common. By using callbacks, we can initiate these operations and specify how our programs should respond once the results are available.
In summary, callbacks are functions that are passed as arguments to other functions and are executed at a later time. They are crucial in asynchronous processing as they allow us to define what should happen once an operation is complete. Understanding callbacks is essential for writing efficient and responsive code in situations where processing needs to occur concurrently.
Reference Articles
Read also
[Google Chrome] The definitive solution for right-click translations that no longer come up.