カンマ区切りの文字列をオブジェクト内の個別の配列に変換するJavaScript

このような文字列があるとします-

const str = 'dress/cotton/black, dress/leather/red, dress/fabric, houses/restaurant/small, houses/school/big, person/james';

そのような文字列を1つ取り込むJavaScript関数を作成する必要があります。次に、関数は次のような配列のオブジェクトを準備する必要があります-

const output = {
   dress = ["cotton","leather","black","red","fabric"];
   houses = ["restaurant","school","small","big"];
   person = ["james"];
};

例

const str = 'dress/cotton/black, dress/leather/red, dress/fabric, houses/restaurant/small, houses/school/big, person/james';
const buildObject = (str = '') => {
   const result = {};
   const strArr = str.split(', ');
   strArr.forEach(el => {
      const values = el.split('/');
      const key = values.shift();
      result[key] = (result[key] || []).concat(values);
   });
   return result;
};
console.log(buildObject(str));

出力

そして、コンソールの出力は-

{
   dress: [ 'cotton', 'black', 'leather', 'red', 'fabric' ],
   houses: [ 'restaurant', 'small', 'school', 'big' ],
   person: [ 'james' ]
}