Array extension method for safe index queries (Swift).

Array+Utilities.swift

import Foundation

extension Array {
    
    /// Safely provides the element at the requested index without encountering those dreaded index out of range errors 🥳.
    ///
    /// Take, for example, an array of characters.
    /// ````
    /// let characters: [Character] = ["a", "b", "c", "d", "e"]
    /// ````
    /// If the provided index lies within the indices of the array, the method will return the element at that index, as normal.
    /// ````
    /// characters.at(0) // returns character "a"
    /// characters.at(4) // returns character "e"
    /// ````
    /// If the provided index exceeds the maximum index of the array, the method will wrap around and start again from index `0`.
    /// ````
    /// characters.at(5) // returns character "a"
    /// characters.at(6) // returns character "b"
    /// ````
    /// Similarly, if the provided index is negative, the method will wrap around but in the reverse direction.
    /// ````
    /// characters.at(-1) // returns character "e"
    /// characters.at(-2) // returns character "d"
    /// ````
    ///
    /// - Parameters:
    ///   - index: The index to provide an element for.
    func at(_ index: Index) -> Element {
        guard indices.contains(index) else {
            let overlap = index % count
            
            if overlap < 0 {
                return self[count + overlap]
            } else {
                return self[overlap]
            }
        }
        
        return self[index]
    }
    
}