Sort object with leading zeros

JavaScript

const plain_options = { 
  "1001": "Freizeile",
  "1101": "Freizeile",
  "1201": "Zwischenmahlzeit",
  "1301": "Zwischenmahlzeit",
  "0101": "Frühstück",
  "0201": "Freizeile",
  "0301": "Freizeile",
  "0401": "Menü A",
  "0501": "Menü B",
  "0601": "Freizeile",
  "0701": "Freizeile",
  "0801": "Mittag 1",
  "0901": "Mittag 2"
};

function sortObjectByKeyParseInt(obj) {
    const sortedKeys = Object.keys(obj).sort((a, b) => parseInt(a, 10) - parseInt(b, 10));
     const sortedObj = {};
     sortedKeys.forEach(key => {
         sortedObj[key] = obj[key];
    });
    return sortedObj;
}

var sorted_options_parse_int = sortObjectByKeyParseInt(plain_options);
console.log('ParseInt: ', sorted_options_parse_int);

options = '';
Object.entries(sorted_options_parse_int).forEach((item) => {
 console.log('Item: ', item);
 options += '<option value="'+item[0]+'"><b>'+item[1]+'</b></option>';
});