property-observer – Tarik Billa

Property observers willSet and didSet; Property getters and setters

May 2, 2023 by Tarik

When and why should I use willSet/didSet willSet is called just before the value is stored. didSet is called immediately after the new value is stored. Consider your example with outputs: var variable1 : Int = 0 { didSet{ print(“didSet called”) } willSet(newValue){ print(“willSet called”) } } print(“we are going to add 3”) variable1 = … Read more

What is the purpose of willSet and didSet in Swift?

September 30, 2022 by Tarik

The point seems to be that sometimes, you need a property that has automatic storage and some behavior, for instance to notify other objects that the property just changed. When all you have is get/set, you need another field to hold the value. With willSet and didSet, you can take action when the value is … Read more