Swift Closures

We can think of closure as simply another way to write a function. It is simply a block of code that can be passed around to other functions.

No parameter

Let's say a simple function that receives no parameter and returns void:

func doSomething() {
	//Do some work
}

This can be written in a closure syntax:

let doSomething = {
	//Do some work
}

this assigns the block/closure to doSomething can now be called just like a regular function.

With parameter

If a function contains a single or multiple parameters:

func getTotalOf(firstNumber: Int, secondNumber: Int) -> Int {
	return firstNumber+secondNumber
}

let result = getTotalOf(firstNumber: 1, secondNumber: 2)

print(result) //3

This is how you would write it in closure:

let getTotalOf = { (firstNumber: Int, secondNumber: Int) in
	return firstNumber+secondNumber
}

// We can call it just like the function above:
let result = getTotalOf(firstNumber: 1, secondNumber: 2)

print(result) //3