Get a random date between two values. Swift 4.2+ uses Random(in:).

Data+Extensions.swift

import Foundation

extension Date {
    
    static func randomBetween(start: String, end: String, format: String = "yyyy-MM-dd") -> String {
        let date1 = Date.parse(start, format: format)
        let date2 = Date.parse(end, format: format)
        return Date.randomBetween(start: date1, end: date2).dateString(format)
    }

    static func randomBetween(start: Date, end: Date) -> Date {
        var date1 = start
        var date2 = end
        if date2 < date1 {
            let temp = date1
            date1 = date2
            date2 = temp
        }
        let span = TimeInterval.random(in: date1.timeIntervalSinceNow...date2.timeIntervalSinceNow)
        return Date(timeIntervalSinceNow: span)
    }

    func dateString(_ format: String = "yyyy-MM-dd") -> String {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = format
        return dateFormatter.string(from: self)
    }

    static func parse(_ string: String, format: String = "yyyy-MM-dd") -> Date {
        let dateFormatter = DateFormatter()
        dateFormatter.timeZone = NSTimeZone.default
        dateFormatter.dateFormat = format

        let date = dateFormatter.date(from: string)!
        return date
    }
}

@nbasham, that is so nice to hear! It's awfully rare to find encouraging words in these places (here and StackExchange, namely). Thank you for taking the time to say that! You truly made my day!

Unfortunately, I can't take credit for the min/max bit, as that was @BrightScreenTV's idea.

I hear you about respecting the user's choices. The guard statement is a better / cleaner / more respectful way to accomplish what I was trying to. Thank you for sharing your code and your wisdom, sir!