Emojis, much like the unicode standard, are deceptively complicated. Skin tones, genders, jobs, groups of people, zero-width joiner sequences, flags (2 character unicode) and other complications can make emoji parsing messy. A Christmas Tree, a Slice of Pizza, or a Pile of Poop can all be represented with a single Unicode code point. Not to mention that when new emojis are introduced, there is a delay between iOS support and emoji release. That and the fact that different versions of iOS support different versions of the unicode standard.
TL;DR. I have worked on these features and opened sourced a library I am the author for JKEmoji to help parse strings with emojis. It makes parsing as easy as:
print("I love these emojis