Swift extension that creates a Unicode flag emoji for the given ISO region/country code.

String+EmojiFlag.swift

public extension String {
    fileprivate static let unicodeFlagsBase = 0x1F1E6 - UInt32("A")

    /// Creates a Unicode flag emoji for the given ISO region/country code.
    ///
    ///     String(flag: "CH") // returns "🇨🇭"
    ///     String(flag: "in") // returns "🇮🇳"
    ///     String(flag: "eu") // returns "🇪🇺"
    ///     String(flag: "42") // returns nil
    ///
    /// - Parameter code: An ISO region code, for example, "CH".
    init?(flag code: String) {
        let code = code.uppercased().filter(\.isUppercase).prefix(2)
        guard code.count == 2 else { return nil }
        self = String(
            code.unicodeScalars.compactMap { UnicodeScalar(Self.unicodeFlagsBase + $0.value) }.map(Character.init)
        )
    }
}

print(Locale.isoRegionCodes.compactMap(String.init(flag:)).joined())

🇦🇨🇦🇩🇦🇪🇦🇫🇦🇬🇦🇮🇦🇱🇦🇲🇦🇴🇦🇶🇦🇷🇦🇸🇦🇹🇦🇺🇦🇼🇦🇽🇦🇿🇧🇦🇧🇧🇧🇩🇧🇪🇧🇫🇧🇬🇧🇭🇧🇮🇧🇯🇧🇱🇧🇲🇧🇳🇧🇴🇧🇶🇧🇷🇧🇸🇧🇹🇧🇻🇧🇼🇧🇾🇧🇿🇨🇦🇨🇨🇨🇩🇨🇫🇨🇬🇨🇭🇨🇮🇨🇰🇨🇱🇨🇲🇨🇳🇨🇴🇨🇵🇨🇶🇨🇷🇨🇺🇨🇻🇨🇼🇨🇽🇨🇾🇨🇿🇩🇪🇩🇬🇩🇯🇩🇰🇩🇲🇩🇴🇩🇿🇪🇦🇪🇨🇪🇪🇪🇬🇪🇭🇪🇷🇪🇸🇪🇹🇫🇮🇫🇯🇫🇰🇫🇲🇫🇴🇫🇷🇬🇦🇬🇧🇬🇩🇬🇪🇬🇫🇬🇬🇬🇭🇬🇮🇬🇱🇬🇲🇬🇳🇬🇵🇬🇶🇬🇷🇬🇸🇬🇹🇬🇺🇬🇼🇬🇾🇭🇰🇭🇲🇭🇳🇭🇷🇭🇹🇭🇺🇮🇨🇮🇩🇮🇪🇮🇱🇮🇲🇮🇳🇮🇴🇮🇶🇮🇷🇮🇸🇮🇹🇯🇪🇯🇲🇯🇴🇯🇵🇰🇪🇰🇬🇰🇭🇰🇮🇰🇲🇰🇳🇰🇵🇰🇷🇰🇼🇰🇾🇰🇿🇱🇦🇱🇧🇱🇨🇱🇮🇱🇰🇱🇷🇱🇸🇱🇹🇱🇺🇱🇻🇱🇾🇲🇦🇲🇨🇲🇩🇲🇪🇲🇫🇲🇬🇲🇭🇲🇰🇲🇱🇲🇲🇲🇳🇲🇴🇲🇵🇲🇶🇲🇷🇲🇸🇲🇹🇲🇺🇲🇻🇲🇼🇲🇽🇲🇾🇲🇿🇳🇦🇳🇨🇳🇪🇳🇫🇳🇬🇳🇮🇳🇱🇳🇴🇳🇵🇳🇷🇳🇺🇳🇿🇴🇲🇵🇦🇵🇪🇵🇫🇵🇬🇵🇭🇵🇰🇵🇱🇵🇲🇵🇳🇵🇷🇵🇸🇵🇹🇵🇼🇵🇾🇶🇦🇷🇪🇷🇴🇷🇸🇷🇺🇷🇼🇸🇦🇸🇧🇸🇨🇸🇩🇸🇪🇸🇬🇸🇭🇸🇮🇸🇯🇸🇰🇸🇱🇸🇲🇸🇳🇸🇴🇸🇷🇸🇸🇸🇹🇸🇻🇸🇽🇸🇾🇸🇿🇹🇦🇹🇨🇹🇩🇹🇫🇹🇬🇹🇭🇹🇯🇹🇰🇹🇱🇹🇲🇹🇳🇹🇴🇹🇷🇹🇹🇹🇻🇹🇼🇹🇿🇺🇦🇺🇬🇺🇲🇺🇸🇺🇾🇺🇿🇻🇦🇻🇨🇻🇪🇻🇬🇻🇮🇻🇳🇻🇺🇼🇫🇼🇸🇽🇰🇾🇪🇾🇹🇿🇦🇿🇲🇿🇼