dropdown.js

import React, { useState, useEffect } from "react";
import styles from "./dropdown.module.scss";

const Dropdown = ({ children, title, ...rest }) => {
  const focusStyle = styles.dropdown__focus;
  const [focusClass, setFocusClass] = useState("");
  const [focus, setFocus] = useState(false);

  useEffect(() => {
    if(focus) {
      setFocusClass(focusStyle);
    } else {
      setFocusClass("");
    }
  }, [focus]);

  const handleKeyDown = event => {
    if(event.key === "Enter") {
      setFocus(!focus);
    }
  };

  return (
    <div
      {...rest}
      tabIndex="0"
      role="button"
      onKeyPress={handleKeyDown}
      onClick={() => setFocus(!focus)}
      onBlur={() =>setFocus(false)}
      className={`${styles.dropdown} ${focusClass}`}
    >
      <span>{title}</span>
      <span className={styles.dropdown__icon}>
        <i className="fas fa-chevron-down" />
      </span>
      <ul className={styles.dropdown__ul}>{children}</ul>
    </div>
  );
};

const Option = ({ children, ...rest }) => (
  <li className={styles.dropdown__li} {...rest}>
    {children}
  </li>
);

export { Dropdown as default, Option };

dropdown.module.scss

.dropdown {
  position: relative;
  border: 1px solid #DDD;
  border-radius: 5px;
  padding: .5rem .75rem;
  display: flex;
  align-items: center;
  cursor: pointer;
  outline: none;

  &:not(.dropdown__focus):hover {
    border: 1px solid #1e90ff;
    color: #1e90ff;
  }
}

.dropdown__ul {
  list-style: none;
  margin: 0;
  padding: 0;
  position: absolute;
  top: calc(100% + 5px);
  right: 0;
  z-index: 999;
  visibility: hidden;
  border: 1px solid #DDD;
  outline: none;
  background: #FFF;
  padding: .5rem;
  border-radius: 5px;
}

.dropdown__li {
  padding: .5rem;
  border-radius: 5px;
  white-space: nowrap;

  &:hover {
    color: #1e90ff;
    background: rgba($color: #1e90ff, $alpha: .1);
  }

  &.disabled {
    color: #999;
    cursor: not-allowed;
  }
}

.dropdown__icon {
  font-size: 12px;
  margin-left: .5rem;
}

.dropdown__focus {
  box-shadow: 0 0 0 3px rgba($color: #1e90ff, $alpha: .5);

  ul {
    visibility: visible;
  }
}