![[Swift] - Clousure cheatsheet](https://image.pollinations.ai/prompt/software%20programming%20code%20dark%20terminal%20clean%20minimalist%20technology%20%5BSwift%5D%20-%20Clousure%20cheatsheet?width=1200&height=630&seed=5985&model=flux&nologo=true)
As a variable :
var closureName: (ParameterTypes) -> ReturnType
As an optional variable :
var closureName: ((ParameterTypes) -> ReturnType)?
As a type alias :
typealias ClosureType = (ParameterTypes) -> ReturnType
As a constant :
let closureName: ClosureType = { ... }
As a parameter to another function :
funcName(parameter: (ParameterTypes) -> ReturnType)
Note: if the passed-in closure is going to outlive the scope of the method, e.g. if you are saving it to a property, it needs to be annotated with @escaping.
As an argument to a function call :
funcName({ (ParameterTypes) -> ReturnType in statements })
As a function parameter :
array.sorted(by: { (item1: Int, item2: Int) -> Bool in return item1 < item2 })
As a function parameter with implied types :
array.sorted(by: { (item1, item2) -> Bool in return item1 < item2 })
As a function parameter with implied return type :
array.sorted(by: { (item1, item2) in return item1 < item2 })
As the last function parameter :
array.sorted { (item1, item2) in return item1 < item2 }
As the last parameter, using shorthand argument names :
array.sorted { return $0 < $1 }
As the last parameter, with an implied return value :
array.sorted { $0 < $1 }
As the last parameter, as a reference to an existing function :
array.sorted(by: <)
As a function parameter with explicit capture semantics :
array.sorted(by: { [unowned self] (item1: Int, item2: Int) -> Bool in return item1 < item2 })
As a function parameter with explicit capture semantics and inferred parameters / return type :
array.sorted(by: { [unowned self] in return $0 < $1 })
