Why is there an error with map in react?

Question

React

Good afternoon. Please tell me why in the code when you try to go through map, an error occurs in the block with map exactly.
'Cannot read properties of undefined (reading 'map')'
Am I wrong?

import { useEffect, useState } from "react";
import "./styles.css";

export default function App() {
  const [load, setLoading] = useState(true);
  const [data, setData] = useState();
  useEffect(() => {
    const fetchData = async() => {
      const res = await fetch('https://jsonplaceholder.typicode.com/comments');
      const data = await res.json()
      setData(data)
    }
    fetchData()
  }, [load])

  console.log(data)

  return (
    <div className="App">
      <h1>Hello Code</h1>
      {data.map((item, idx) => (
        <div key={idx}>
          <h2>{item.name}</h2>
        </div>
      ))}
    </div>
  );
}

Answer 1

const [data, setData] = useState([]);
Now in order you have this:
1.

const [data, setData] = useState(); // data === undefined

2. 3. 4. Numbers flow through wires... 5. 6.data.map((item, idx) => ( // error
data.map((item, idx) => ( // ok