JSFiddle - React, Tailwind, and code Playground

HTML

<p>※最低2文字入力する必要があります</p>
<p><input autofocus class="awesomplete" data-list="りんご, ごりら, らんでぶー, ぶるじょわ, わいるどだろ, ろーるすろいす, すとーりー" /></p>
<p>設定キーワードは<br>
「りんご, ごりら, らんでぶー, ぶるじょわ, わいるどだろ, <br>ろーるすろいす, すとーりー」</p>

CSS

[hidden] {
    display: none;
}

div.awesomplete {
    display: inline-block;
    position: relative;
}

div.awesomplete > input {
    display: block;
}

div.awesomplete > ul {
    position: absolute;
    left: 0;
    z-index: 1;
    min-width: 100%;
    box-sizing: border-box;
    list-style: none;
    padding: 0;
    border-radius: .3em;
    margin: .2em 0 0;
    background: hsla(0,0%,100%,.9);
    background: linear-gradient(to bottom right, white, hsla(0,0%,100%,.8));
    border: 1px solid rgba(0,0,0,.3);
    box-shadow: .05em .2em .6em rgba(0,0,0,.2);
    text-shadow: none;
}

div.awesomplete > ul[hidden],
div.awesomplete > ul:empty {
    display: none;
}

@supports (transform: scale(0)) {
    div.awesomplete > ul {
        transition: .3s cubic-bezier(.4,.2,.5,1.4);
        transform-origin: 1.43em -.43em;
    }

    div.awesomplete > ul[hidden],
	div.awesomplete > ul:empty {
        opacity: 0;
        transform: scale(0);
        display: block;
        transition-timing-function: ease;
    }
}

	/* Pointer */
div.awesomplete > ul:before {
    content: "";
    position: absolute;
    top: -.43em;
    left: 1em;
    width: 0;
    height: 0;
    padding: .4em;
    background: white;
    border: inherit;
    border-right: 0;
    border-bottom: 0;
    -webkit-transform: rotate(45deg);
    transform: rotate(45deg);
}

div.awesomplete > ul > li {
    position: relative;
    padding: .2em .5em;
    cursor: pointer;
}

div.awesomplete > ul > li:hover {
    background: hsl(200, 40%, 80%);
    color: black;
}

div.awesomplete > ul > li[aria-selected="true"] {
    background: hsl(205, 40%, 40%);
    color: white;
}

div.awesomplete mark {
    background: hsl(65, 100%, 50%);
}

div.awesomplete li:hover mark {
    background: hsl(68, 101%, 41%);
}

div.awesomplete li[aria-selected="true"] mark {
    background: hsl(86, 102%, 21%);
    color: inherit;
}

JavaScript

/**
 * Simple, lightweight, usable local autocomplete library for modern browsers
 * Because there weren’t enough autocomplete scripts in the world? Because I’m completely insane and have NIH syndrome? Probably both. :P
 * @author Lea Verou http://leaverou.github.io/awesomplete
 * MIT license
 */

(function() {

    var _ = self.Awesomplete = function(input, o) {
        var me = this;

        // Setup

        this.input = input;
        input.setAttribute("aria-autocomplete", "list");

        o = o || {};

        configure.call(this, {
            minChars: 2,
            maxItems: 10,
            autoFirst: false,
            filter: _.FILTER_CONTAINS,
            sort: _.SORT_BYLENGTH,
            item: function(text, input) {
                return $.create("li", {
                    innerHTML: text.replace(RegExp($.regExpEscape(input.trim()), "gi"), "<mark>$&</mark>"),
                    "aria-selected": "false"
                });
            },
            replace: function(text) {
                this.input.value = text;
            }
        }, o);

        this.index = -1;

        // Create necessary elements

        this.container = $.create("div", {
            className: "awesomplete",
            around: input
        });

        this.ul = $.create("ul", {
            hidden: "",
            inside: this.container
        });

        // Bind events

        $.bind(this.input, {
            "input": this.evaluate.bind(this),
            "blur": this.close.bind(this),
            "keydown": function(evt) {
                var c = evt.keyCode;

                if (c === 13 && me.selected) { // Enter
                    evt.preventDefault();
                    me.select();
                } else if (c === 27) { // Esc
                    me.close();
                } else if (c === 38 || c === 40) { // Down/Up arrow
                    evt.preventDefault();
                    me[c === 38 ? "previous" : "next"]();
                }
          ...