Emoji Checking for Swift 5.0 and up

String+EmojiCheck.swift

import Foundation

// Source: https://stackoverflow.com/a/39425959

extension Character {
    /// A simple emoji is one scalar and presented to the user as an Emoji
    var isSimpleEmoji: Bool {
        guard let firstScalar = unicodeScalars.first else { return false }
        return firstScalar.properties.isEmoji && firstScalar.value > 0x238C
    }

    /// Checks if the scalars will be merged into an emoji
    var isCombinedIntoEmoji: Bool { unicodeScalars.count > 1 && unicodeScalars.first?.properties.isEmoji ?? false }

    var isEmoji: Bool { isSimpleEmoji || isCombinedIntoEmoji }
}

extension String {
    var isSingleEmoji: Bool { count == 1 && containsEmoji }

    var containsEmoji: Bool { contains { $0.isEmoji } }

    var containsOnlyEmoji: Bool { !isEmpty && !contains { !$0.isEmoji } }

    var emojiString: String { emojis.map { String($0) }.reduce("", +) }

    var emojis: [Character] { filter { $0.isEmoji } }

    var emojiScalars: [UnicodeScalar] { filter { $0.isEmoji }.flatMap { $0.unicodeScalars } }
}

// Examples...

"A̛͚̖".containsEmoji // false
"3".containsEmoji // false
"A̛͚̖▶️".unicodeScalars // [65, 795, 858, 790, 9654, 65039]
"A̛͚̖▶️".emojiScalars // [9654, 65039]
"3️⃣".isSingleEmoji // true
"3️⃣".emojiScalars // [51, 65039, 8419]
"👌🏿".isSingleEmoji // true
"🙎🏼‍♂️".isSingleEmoji // true
"🇹🇩".isSingleEmoji // true
"⏰".isSingleEmoji // true
"🌶".isSingleEmoji // true
"👨‍👩‍👧‍👧".isSingleEmoji // true
"🏴󠁧󠁢󠁳󠁣󠁴󠁿".isSingleEmoji // true
"🏴󠁧󠁢󠁥󠁮󠁧󠁿".containsOnlyEmoji // true
"👨‍👩‍👧‍👧".containsOnlyEmoji // true
"Hello 👨‍👩‍👧‍👧".containsOnlyEmoji // false
"Hello 👨‍👩‍👧‍👧".containsEmoji // true
"👫 Héllo 👨‍👩‍👧‍👧".emojiString // "👫👨‍👩‍👧‍👧"
"👨‍👩‍👧‍👧".count // 1

"👫 Héllœ 👨‍👩‍👧‍👧".emojiScalars // [128107, 128104, 8205, 128105, 8205, 128103, 8205, 128103]
"👫 Héllœ 👨‍👩‍👧‍👧".emojis // ["👫", "👨‍👩‍👧‍👧"]
"👫 Héllœ 👨‍👩‍👧‍👧".emojis.count // 2

"👫👨‍👩‍👧‍👧👨‍👨‍👦".isSingleEmoji // false
"👫👨‍👩‍👧‍👧👨‍👨‍👦".containsOnlyEmoji // true

Updated version of the code which originally comes from: https://stackoverflow.com/a/39425959