What is the correct way to use strongSelf in fast?

Question

In Objective-C, in non-trivial blocks, I noticed the use of weakSelf / strongSelf.

What is the correct way to use strongSelf in Swift? Sort of:

if let strongSelf = self { strongSelf.doSomething() } 

So, for every line containing self in close, should I add a strongSelf check?

 if let strongSelf = self { strongSelf.doSomething1() } if let strongSelf = self { strongSelf.doSomething2() } 

Is there a way to make the above more elegant?

Answer 1

Using strongSelf is a way to verify that self not nil. When you have a closure that may be triggered at some point in the future, it is important to pass an instance of weak self so that you do not create a save loop while maintaining references to objects that have been de-initialized.

 {[weak self] () -> void in if let strongSelf = self { strongSelf.doSomething1() } } 

Essentially, you say that if I no longer exist, do not keep a link to it and do not perform an action on it.

Answer 2

another way to use weak self without using strongSelf

 {[weak self] () -> void in guard let `self` = self else { return } self.doSomething() } 

Answer 3

Swift 4.2 🔸

 guard let self = self else { return } 

Link: https://benscheirman.com/2018/09/capturing-self-with-swift-4-2/
Ref2: https://www.raywenderlich.com/5370-grand-central-dispatch-tutorial-for-swift-4-part-1-2

Answer 4

Your use of strongSelf seems directional only when you call the doSomethingN() method, if self not equal to zero. Use the preferred method instead:

 self?.doSomethingN() 

Answer 5

If you use self in your closure, it is automatically used as strong.

There is also a way to use as weak or unowned if you are trying to avoid save cycles. This is achieved by skipping [unoccupied self] or [weak self] before closing parameters.