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Khoa Pham
Khoa Pham

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How to deal with weak in closure in Swift

#swift #ios #closure #weak

Traditionally we need to if let to strongSelf

addButton.didTouch = { [weak self] in guard let strongSelf = self, let product = strongSelf.purchasedProduct() else { return strongSelf.delegate?.productViewController(strongSelf, didAdd: product) }

This is cumbersome, we can invent a higher order function to zip and unwrap the optionals

func with<A, B>(_ op1: A?, _ op2: B?, _ closure: (A, B) -> Void) { if let value1 = op1, let value2 = op2 { closure(value1, value2) } } addButton.didTouch = { [weak self] in with(self, self?.purchasedProduct()) { $0.delegate?.addProductController($0, didIncrease: $1) } }

Original post https://github.com/onmyway133/blog/issues/326

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