Formats bytes into a more human-readable form (e.g. MiB) using Extensions instead of functions

stringFileSize.swift

// Forked from https://gist.github.com/mminer/d0a043b0b6054f428a8ed1f505bfe1b0 to
import Foundation

public extension Double {
	var stringFileSize: String {
		guard self > 0 else {
			return "0 bytes"
		}
		guard self != 1 else {
			return "1 byte"
		}

		// Adapted from http://stackoverflow.com/a/18650828
		let suffixes = ["bytes", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"]
		let k: Double = 1024
		let i = floor(log(self) / log(k))

		// Format number with thousands separator and everything below 1 GB with no decimal places.
		let numberFormatter = NumberFormatter()
		numberFormatter.maximumFractionDigits = i < 3 ? 0 : 2
		numberFormatter.numberStyle = .decimal

		let numberString = numberFormatter.string(from: NSNumber(value: self / pow(k, i))) ?? "Unknown"
		let suffix = suffixes[Int(i)]
		return "\(numberString) \(suffix)"
	}
}

public extension Int {
	var stringFileSize: String {
		return Double(self).stringFileSize
	}
}

/////////////////////////
// Does the following:
print(123123123123123.0.stringFileSize) // 111,98 TiB
print(6969696969.stringFileSize) // 6,49 GiB
print(1.0.stringFileSize) // 1 byte
print(1029.stringFileSize) // 1 KiB