How to Merge array of objects list into single array

Question

I have a list of array of Objects. I need to concat the all the options items into one array. Here is the sample array of objects.

let data = [
  {
    name: "group1",
    options: [
      {
        item: "item1",
        price: 100
      },
      {
        item: "item2",
        price: 200
      },
      {
        item: "item3",
        price: 300
      }
    ]
  },
  {
    name: "group2",
    options: [
      {
        item: "item4",
        price: 101
      },
      {
        item: "item5",
        price: 201
      }
    ]
  },
  {
    name: "group3",
    options: [
      {
        item: "item6",
        price: 254
      },
      {
        item: "item7",
        price: 358
      }
    ]
  }
]

output like:


let options = [
  {
    item: "item1",
    price: 100
  },
  {
    item: "item2",
    price: 200
  },
  {
    item: "item3",
    price: 300
  },
  {
    item: "item4",
    price: 101
  },
  {
    item: "item5",
    price: 201
  },
  {
    item: "item6",
    price: 254
  },
  {
    item: "item7",
    price: 358
  }
]

Clarity · Accepted Answer · 2019-11-25 08:38:53Z

5

You can do it with reduce:

const options = data.reduce((acc, item) => acc.concat(item.options), [])

answered Nov 25, 2019 at 8:38

Clarity

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Comments

Mamun · Accepted Answer · 2019-11-25 10:17:37Z

You can try with Array.prototype.flatMap()

The flatMap() method first maps each element using a mapping function, then flattens the result into a new array. It is identical to a map() followed by a flat() of depth 1, but flatMap() is often quite useful, as merging both into one method is slightly more efficient.

let options = data.flatMap(d => d.options);

let data = [
  {
    name: "group1",
    options: [
      {
        item: "item1",
        price: 100
      },
      {
        item: "item2",
        price: 200
      },
      {
        item: "item3",
        price: 300
      }
    ]
  },
  {
    name: "group2",
    options: [
      {
        item: "item4",
        price: 101
      },
      {
        item: "item5",
        price: 201
      }
    ]
  },
  {
    name: "group3",
    options: [
      {
        item: "item6",
        price: 254
      },
      {
        item: "item7",
        price: 358
      }
    ]
  }
];


let options = data.flatMap(d => d.options);
console.log(options);

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