Why is it recommended to use a weak reference to the object itself (weak self) in code that uses closures?

Using a weak reference (weak self) in closures is necessary to prevent strong reference cycles (retain cycles), which lead to memory leaks.

When a closure captures self as a strong reference, and self contains that closure (for example, in a property), they hold onto each other, and neither object is released.

An example of using a weak reference:

someAsyncCall { [weak self] in
    guard let self = self else { return }
    self.doSomething()
}

Here, self is captured weakly, so if the self object is destroyed before the closure executes, the closure will not hold it in memory, preventing a leak.