otterscan/src/Title.tsx

import React, { useState, useRef } from "react";
import { Link, useHistory } from "react-router-dom";
import useKeyboardShortcut from "use-keyboard-shortcut";

const Title: React.FC = () => {
  const [search, setSearch] = useState<string>();
  const [canSubmit, setCanSubmit] = useState<boolean>(false);
  const history = useHistory();

  const handleChange: React.ChangeEventHandler<HTMLInputElement> = (e) => {
    setCanSubmit(e.target.value.trim().length > 0);
    setSearch(e.target.value.trim());
  };

  const handleSubmit: React.FormEventHandler<HTMLFormElement> = (e) => {
    e.preventDefault();
    if (!canSubmit) {
      return;
    }

    history.push(`/search?q=${search}`);
  };

  const searchRef = useRef<HTMLInputElement>(null);
  useKeyboardShortcut(["/"], () => {
    searchRef.current?.focus();
  });

  return (
    <div className="px-9 py-2 flex justify-between items-baseline">
      <Link className="self-center" to="/">
        <div className="text-2xl text-link-blue font-title font-bold flex items-center space-x-2">
          <img
            className="rounded-full"
            src="/otter.jpg"
            width={32}
            height={32}
            alt="An otter scanning"
            title="An otter scanning"
          />
          <span>Otterscan</span>
        </div>
      </Link>
      <form
        className="flex"
        onSubmit={handleSubmit}
        autoComplete="off"
        spellCheck={false}
      >
        <input
          className="w-full border-t border-b border-l rounded-l focus:outline-none px-2 py-1 text-sm"
          type="text"
          size={60}
          placeholder='Type "/" to search by address / txn hash / block number / ENS name'
          onChange={handleChange}
          ref={searchRef}
        />
        <button
          className="rounded-r border-t border-b border-r bg-gray-100 hover:bg-gray-200 focus:outline-none px-2 py-1 text-sm text-gray-500"
          type="submit"
        >
          Search
        </button>
      </form>
    </div>
  );
};

export default React.memo(Title);