First, here's how Apple's system works. Predictive text must be turned on, and you need to type the entire word to see if Apple suggests an emoji for it.
But this isn't true emoji search: Apple may return two or three emoji suggestions for the word you typed, but those suggestions might not include the emoji you actually want.
On Slack, the communication tool we use at Business Insider, emoji search is extremely easy and intuitive. If you type a word between two colons, like :smile:, it will change into that text into the smile emoji, but also show you all of the available smile emojis.
Better yet, if you type a colon (:), then start typing any word, Slack will autofill with any and all available emojis without needing to type the full word.
Slack even goes the extra mile to let you add your own custom emojis!
Hopefully we get something like this in iOS 14 in 2020. I love all of the new emojis, but I should be able to type :waffle: to get the waffle emoji, instead of needing to scroll through the dozens of food emojis to find it.