错误:无法读取render方法中未定义(状态)的属性'map‘

let obj;
console.log(obj.map); // TypeError: Cannot read property 'map' of undefined

import React, { useState, useEffect } from 'react';

function MyComponent() {
    const [data, setData] = useState([]);

    useEffect(() => {
        fetch('https://api.example.com/data')
            .then(response => response.json())
            .then(data => {
                setData(data);
            });
    }, []);

    return (
        <div>
            {data.map(item => (
                <div key={item.id}>{item.name}</div>
            ))}
        </div>
    );
}

export default MyComponent;