Detects if a string is made up of just emoji (and space).

NSString+EmojiDetection.swift

import Foundation

extension String {
	private static let regex = try! NSRegularExpression(pattern: "^[\\s\n\r]*(?:(?:[\u{a9}\u{ae}\u{203c}\u{2049}\u{2122}\u{2139}\u{2194}-\u{2199}\u{21a9}-\u{21aa}\u{231a}-\u{231b}\u{2328}\u{23cf}\u{23e9}-\u{23f3}\u{23f8}-\u{23fa}\u{24c2}\u{25aa}-\u{25ab}\u{25b6}\u{25c0}\u{25fb}-\u{25fe}\u{2600}-\u{2604}\u{260e}\u{2611}\u{2614}-\u{2615}\u{2618}\u{261d}\u{2620}\u{2622}-\u{2623}\u{2626}\u{262a}\u{262e}-\u{262f}\u{2638}-\u{263a}\u{2648}-\u{2653}\u{2660}\u{2663}\u{2665}-\u{2666}\u{2668}\u{267b}\u{267f}\u{2692}-\u{2694}\u{2696}-\u{2697}\u{2699}\u{269b}-\u{269c}\u{26a0}-\u{26a1}\u{26aa}-\u{26ab}\u{26b0}-\u{26b1}\u{26bd}-\u{26be}\u{26c4}-\u{26c5}\u{26c8}\u{26ce}-\u{26cf}\u{26d1}\u{26d3}-\u{26d4}\u{26e9}-\u{26ea}\u{26f0}-\u{26f5}\u{26f7}-\u{26fa}\u{26fd}\u{2702}\u{2705}\u{2708}-\u{270d}\u{270f}\u{2712}\u{2714}\u{2716}\u{271d}\u{2721}\u{2728}\u{2733}-\u{2734}\u{2744}\u{2747}\u{274c}\u{274e}\u{2753}-\u{2755}\u{2757}\u{2763}-\u{2764}\u{2795}-\u{2797}\u{27a1}\u{27b0}\u{27bf}\u{2934}-\u{2935}\u{2b05}-\u{2b07}\u{2b1b}-\u{2b1c}\u{2b50}\u{2b55}\u{3030}\u{303d}\u{3297}\u{3299}\u{1f004}\u{1f0cf}\u{1f170}-\u{1f171}\u{1f17e}-\u{1f17f}\u{1f18e}\u{1f191}-\u{1f19a}\u{1f201}-\u{1f202}\u{1f21a}\u{1f22f}\u{1f232}-\u{1f23a}\u{1f250}-\u{1f251}\u{200d}\u{1F300}-\u{1F5FF}\u{1F600}-\u{1F64F}\u{1F680}-\u{1F6FF}\u{1F900}-\u{1F9FF}\u{e0020}-\u{e007f}]|\u{200d}[\u{2640}\u{2642}]|[\u{1f1e6}-\u{1f1ff}]{2}|.[\u{20e0}\u{20e3}\u{fe0f}]+)+[\\s\n\r]*)+$", options: [])
	
	var isEmojiOnly: Bool {
		return (String.regex.firstMatchInString(self, options: [], range: NSMakeRange(0, (self as NSString).length)) != nil)
	}
}

func test(string: String, _ isEmoji: Bool) {
	if string.isEmojiOnly != isEmoji {
		print("\(string) should\((isEmoji ? "" : " not")) be emoji only")
	}
}

test("Hello 😲", false)
test("-", false)
test("+", false)
test("$", false)
test("👴🏻", true) // Requires Unicode 8.0 support for skin tones
test(" 👨‍👨‍👧‍👧 ", true)
test(" 0️⃣ ❤️", true)
test("👨‍👨‍👧‍👧 ❤️", true)
test(" 0️⃣ ❤️👨‍👨‍👧‍👧 ", true)
test("0️⃣\n❤️", true)
test("©®🔝🔛🔙💱➕➖➗®©™🔜🔴🔵⚫️⚪️🔹🔘🔸▪️▫️◻️◾️🔉🔇♦️♥️♣️♠️🀄️🎴👁‍🗨💭🗯🕔🕓🕖🕖🕜🕥💬🕎☪☪🔝☑️#️⃣#️⃣⤵️*️⃣ℹ️↩️↪️↙️↘️➡️🔂◀️🔼⏸⏯4️⃣🆓🆖📶🆒🛄🏧🌀💠✅〽️💯⁉️❕🚳🚯🚷🚫❌⭕️💢⛔️🅱㊙️✴️🆚💘💕💚🔎📝🔓🚩🎐🎀⛱🛏🗿🔑🏷🔬🏺🛡⚔🔫🛠🛠💎💴🕯📡⏲📻📞📸💾🖱📲🕍🏯🎇🏙🏜🏞🎢🚥🚦💺🚤🚇🚅🚟🚍🚜🚑🚙🎷🎺🚴🏾🎱🏉🏀🍶🍵🍿🎂🍡🍛🌭🍠🍍🍇⛄️☃🌨☀️☄⭐️🌝🌚🌚🌝🌑🌒🌕🌺🐚🕸🍃🌴🐑🐄🐄🐌🐦🐗🐽🐭💍🕶👓👠👞👨‍👩‍👧‍👦👩‍❤️‍👩🙎🏼💂🏽👥👇🏻👏🏻😿🤕😲😪🙁😟🙄😘😁🐑🌴👓👏🏻😲😘", true)
test("㏎", false)
test("㏷", false)
test("䷑", false)
test("䷫", false)
test("䷽", false)
test("꒞", false)

Added support for flag tags.