Trying to figure out how to apply skin tone modifiers to gemoji

Playground.swift

import Foundation

// Each pair below is a "base" emoji copied from gemoji's emoji.json,
// followed by a modified emoji copied from OS X' "Emoji & Symbols" menu.

// You can run this by copying this file into a Swift playground.
// For readers' convenience, I've printed the output inline below.

// 1.
"🖐️".unicodeScalars.forEach { (c) in
    print(c.escaped(asASCII: true), terminator: "")
}

print("") // \u{0001F590}\u{FE0F}

"🖐🏻".unicodeScalars.forEach { (c) in
    print(c.escaped(asASCII: true), terminator: "")
}

print("") // \u{0001F590}\u{0001F3FB}


// 2.
"💆‍♂️".unicodeScalars.forEach { (c) in
    print(c.escaped(asASCII: true), terminator: "")
}

print("") // \u{0001F486}\u{200D}\u{2642}\u{FE0F}

"💆🏻‍♂️".unicodeScalars.forEach { (c) in
    print(c.escaped(asASCII: true), terminator: "")
}

print("") // \u{0001F486}\u{0001F3FB}\u{200D}\u{2642}\u{FE0F}


// 3.
"🕵️‍♂️".unicodeScalars.forEach { (c) in
    print(c.escaped(asASCII: true), terminator: "")
}

print("") // \u{0001F575}\u{FE0F}\u{200D}\u{2642}\u{FE0F}

"🕵🏻‍♂️".unicodeScalars.forEach { (c) in
    print(c.escaped(asASCII: true), terminator: "")
}

print("") // \u{0001F575}\u{0001F3FB}\u{200D}\u{2642}\u{FE0F}