merging arrays using lodash

Question

I have this set of an array of objects:

let x = [{
    CategoryName: 'abc',
    Items: ['3A']
  },
  {
    CategoryName: 'xyz',
    Items: ['5Z']
  },
  {
    CategoryName: 'abc',
    Items: ['6B']
  },
  {
    CategoryName: 'abc',
    Items: ['9C']
  },
  {
    CategoryName: 'xyz',
    Items: ['1X']
  }
];

what I want is:

[
    {CategoryName:'abc',Items['3A','6B','9C']},
    {CategoryName:'xyz',Items['1X','5Z']}
]

How I can I achieve this using lodash?

Answer 1

You can group it by CategoryName and flatMap that result by Items. That's it!

_(x).groupBy('CategoryName').map((v, k)=> ({CategoryName: k, Items: _.flatMap(v, 'Items')})).value()

Working demo:

let x = [{"CategoryName":"abc","Items":["3A"]},{"CategoryName":"xyz","Items":["5Z"]},{"CategoryName":"abc","Items":["6B"]},{"CategoryName":"abc","Items":["9C"]},{"CategoryName":"xyz","Items":["1X"]}],
    res;
    
res = _(x).groupBy('CategoryName').map((v, k)=> ({CategoryName: k, Items: _.flatMap(v, 'Items')})).value();

console.log(res);

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