A complete guide to the Swift defer statement

Swift's defer statement is a powerful tool for ensuring that specific actions are performed before exiting a scope, regardless of how the exit occurs. Introduced in 2016, the defer keyword is especially useful for performing cleanup tasks, such as unlocking locks, committing changes, or updating layouts, which might otherwise be forgotten in complex code paths. Despite its utility, defer is not widely used, partly due to a lack of clear examples in Swift documentation. This exploration provides several practical use cases, including networking, layout updates, loading indicators, and unit testing, demonstrating how defer enhances code readability and maintainability. By ensuring that certain operations are always executed before a scope is exited, defer helps to future-proof code against modifications that might otherwise introduce errors.