How to use defer effectively in swift 5

In Swift 5, defer is a control flow statement that lets you schedule a block of code to be executed just before the current scope is exited. It’s often used to handle cleanup tasks such as releasing resources, closing files, or unlocking locks.

Here’s an example of how to use defer effectively in Swift 5:

func processFile() throws {
    let file = openFile()
    defer {
        file.close()
    }
    // Do some work with the file
    // If an error occurs, the defer block will still be executed
    // and the file will be closed.
}

In this example, the openFile() function returns a file object that needs to be closed when we’re finished with it. We use defer to schedule the call to file.close() just before the processFile() function exits, ensuring that the file is always closed regardless of whether an error occurred or not.

Here are some tips for using defer effectively in Swift 5:

1. Place defer statements close to the code they’re associated with to make it clear what resources they’re releasing.
2. Use multiple defer statements if necessary to release multiple resources.
3. Use defer to ensure that code is executed even in the event of an error or early return.
4. Avoid using defer for performance-critical code, since there is a small overhead associated with executing deferred statements.

By using defer effectively in your Swift code, you can ensure that your resources are always released in a timely and reliable manner.