Instead of manually checking if index is is valid, extend `Collection` creating a subscript that returns an optional element.

###### Standard:
```swift
[!copy]
let array = ["John", "Mike"]

let name = array[1] // "Mike"
let name = array[2] // Crash
```

###### With the extension:
```swift
[!copy]
let array = ["John", "Mike"]

let name = array[safe: 1] // "Mike"
let name = array[safe: 2] // nil
```

---

###### The extension:
```swift
[copy]
extension Collection {
	subscript(safe index: Index) -> Element? {
		return indices.contains(index) ? self[index] : nil
	}
}
```

Safe subscript protects the collection from out of bounds error by using optionals.

Safe Collection Subscript

Swift

Standard:

With the extension:

The extension: