CODEX

Swift 5: Closures Made Simple [Updated in 2022]

Closures are an important concept. This guide aims to make them as simple as possible.

Photo by Joshua Aragon on Unsplash

Swift Closures in Short

Swift closure is a special type of function. Similar to regular functions, closures accept parameters, execute statements, and return values.

According to Apple:

Closures are self-contained blocks of functionality that can be passed around and used in your code

In Swift, you can use closures as

• Higher-order functions, such as when sorting or filtering a list.
• Completion handlers to call back after a lengthy task has finished.

Swift Closures

Let’s start by writing a closure to demonstrate how it works:

let greet = {
    print("Hello!")
}
greet()

Output:

"Hello!"

Let’s break it down:

• We create a constant greet in which we assign a closure. The closure is all the code after the equals sign.
• We call greet in a similar fashion as if it was a function.