Map array of objects with same key using reduce

custom;js

const items = [
  {
    key: 'categoryA',
    sequence: 1
  },
  {
    key: 'categoryB',
    sequence: 2
  },
  {
    key: 'categoryA',
    sequence: 3
  },
  {
    key: 'categoryB',
    sequence: 4
  },  
];

const result = items.reduce((prev, curr) => {
  if (!prev.hasOwnProperty(curr.key)) {
    prev[curr.key] = [];
  }
  prev[curr.key].push(curr);
  return prev;
}, {});

console.log(result);
/*
{
    "categoryA": [
        {
            "key": "categoryA",
            "sequence": 1
        },
        {
            "key": "categoryA",
            "sequence": 3
        }
    ],
    "categoryB": [
        {
            "key": "categoryB",
            "sequence": 2
        },
        {
            "key": "categoryB",
            "sequence": 4
        }
    ]
}
*/