To get sideBar like amazon

hello everyone in the StackOverflow community, I wanna try to have a sidebar like amazon but I fail to have the same. As I see all data of my code is working very well I try it all with the console.log() function. But the inverse happens when I try to use it in the component function it doesn’t work as I want. It doesn’t display the subcategories list under every header category. it returns this error:

Uncaught TypeError: Cannot read properties of undefined (reading ‘map’).
at CategoriesBar.js:69:1

This is my code:

import {useState, useEffect} from "react";
import List from '@mui/material/List';
import ListItem from '@mui/material/ListItem';
import ListItemText from '@mui/material/ListItemText';
import ListSubheader from '@mui/material/ListSubheader';
import {Link} from "react-router-dom";
import axios from "axios";





 function CategoriesBar() {
  
  let [subCategories, setSubCategories] = useState({});
   let [dataCategories, setDataCategories] = useState([]);
  
   const getCategories = async() => {
      await axios.get("/api/categories")
      .then(res => res.data)
      .then(data => setDataCategories(data))
      .catch(err => console.log(err));
};

   const getSubCategories = async() => {
    let newSub ={};
    try {
     if(dataCategories.length !== 0) {
        dataCategories.forEach(async(category,i) => {
         const response = await axios.get(`/api/subcategories/${category.id}`)
          const {subcategories} = response.data;
         let subName = subcategories.map(sub => sub.name);
          newSub[category.name] = subName;
         })
         
      
        setSubCategories(newSub);
        localStorage.setItem("subcategories", newSub);
     } else {
     return
    }
  }catch(err) {
    console.log(err)
  }
   }
   
  useEffect(()=> {
    getCategories()
    .then(()=> getSubCategories())
     
}, []);


console.log(subCategories)
 return (
 
    <div>
    <div className="text-white font-bold bg-green-700 pt-2.5 pl-2 pb-2.5 pr-8 w-96 text-2xl">
          <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={1.5} stroke="currentColor" className="w-10 inline-block pr-2 ">
  <path strokeLinecap="round" strokeLinejoin="round" d="M17.982 18.725A7.488 7.488 0 0012 15.75a7.488 7.488 0 00-5.982 2.975m11.963 0a9 9 0 10-11.963 0m11.963 0A8.966 8.966 0 0112 21a8.966 8.966 0 01-5.982-2.275M15 9.75a3 3 0 11-6 0 3 3 0 016 0z" />
</svg>
 Hello, Sign In
      </div>
    <List sx={{
      width: '100%',
        maxWidth: 384,
        bgColor: 'background.paper',
        position: 'absolute',
        overflowY: 'scroll',
        height: '100%',
        '& ul': { padding: 0 }
      }}
      subheader={<li />} >
        
      {dataCategories.length !==0 && dataCategories.map(item => item.name).map((category, index) => (
        <li key={index}>
          <ul>
            <ListSubheader sx={{fontWeight:"bold", color: "black", fontSize: 24, marginTop: 3}} >{category}</ListSubheader>
              {subCategories[category].map((item, index) => (
              <ListItem key={index}> 
                <ListItemText primary={item} />
              </ListItem>
             ))}
          </ul>
        </li>
      
        ))}
      </List>
              </div>
    )};

export default CategoriesBar;