10 Powerful @Attributes in Swift

Understand how to use the attributes correctly and efficiently

Photo by Nathan Dumlao on Unsplash.

@escaping

It’s normally used as an escaping closure passed as a function argument. It exists in the memory when the function ends and then gets executed.

When defining an optional closure as a property, it’s already escaping by default.

The escaping closure can be stored for later use:

Or it can be executed after the function ends:

@unknown

@unknown was introduced with @frozen and @nonfrozen enumerations. A non-frozen enum may gain new enumeration cases in the future. For instance, the UILayoutConstraintAxis contains two axes at the moment: AxisHorizontal and AxisVertical:

It may gain another case axisZ later:

To safely avoid the compile error:

error: switch must be exhaustive