I have this array of arrays with objects:

const data = [
  [
    {
      index: 320,
      blocks: 2,
      value: '31011784785',
      participants: 1222,
      cost: '1286828506'
    },
    {
      index: 319,
      blocks: 0,
      value: '111306385',
      participants: 18,
      cost: '0'
    },
    {
      index: 318,
      blocks: 0,
      value: '14550473',
      participants: 10,
      cost: '0'
    }
  ],
  [
    {
      index: 320,
      blocks: 1,
      value: '7089001673',
      participants: 492,
      cost: '648196615'
    },
    {
      index: 319,
      blocks: 0,
      value: '13551137',
      participants: 8,
      cost: '0'
    },
    {
      index: 318,
      blocks: 0,
      value: '11499815',
      participants: 5,
      cost: '0'
    }
  ],
  [
    {
      index: 320,
      blocks: 1,
      value: '408900161',
      participants: 200,
      cost: '648196615'
    },
    {
      index: 319,
      blocks: 0,
      value: '23551231',
      participants: 10,
      cost: '0'
    },
    {
      index: 318,
      blocks: 0,
      value: '104324219',
      participants: 5,
      cost: '0'
    }
  ]
]

I would like to make a single array with objects that will have just the properties index, value, and participants where value and participants will be the sum of the 3 arrays. Eg:

[
  {
      index: 320,
      value: 38509686619,
      participants: 1914,
  },
  {
      index: 319,
      value: 148408753,
      participants: 36,
  },
  {
     ...
  }
]

I would also like the value field to be a BigInt.

Inspired by this answer I made something that works but it's way too long and cumbersome.

This question is different from Reduce Array of Array of Objects Using Ramda because I need two object property values and I don't know how to do this.

CodePudding user response：

After flattening, the array of arrays, you should map and pick the wanted properties and convert values to a number, and then group by, and combine each group to a single object.

const { mergeWithKey, pipe, flatten, map, pick, evolve, groupBy, prop, reduce, values } = R

// merge deep and combine properties value
const combine = mergeWithKey((k, l, r) => k === 'value' || k === 'participants' ? l   r : r)

const mergeData = pipe(
  flatten, // flatten to a single array
  map(pipe(
    pick(['index', 'value', 'participants']), // pick wanted properties
    evolve({ value: Number }) // convert values to a number
  )),
  groupBy(prop('index')), // group by the name
  map(reduce(combine, {})), // combine each group to a single object
  values, // convert back to array
)

const data = [[{"index":320,"blocks":2,"value":"31011784785","participants":1222,"cost":"1286828506"},{"index":319,"blocks":0,"value":"111306385","participants":18,"cost":"0"},{"index":318,"blocks":0,"value":"14550473","participants":10,"cost":"0"}],[{"index":320,"blocks":1,"value":"7089001673","participants":492,"cost":"648196615"},{"index":319,"blocks":0,"value":"13551137","participants":8,"cost":"0"},{"index":318,"blocks":0,"value":"11499815","participants":5,"cost":"0"}],[{"index":320,"blocks":1,"value":"408900161","participants":200,"cost":"648196615"},{"index":319,"blocks":0,"value":"23551231","participants":10,"cost":"0"},{"index":318,"blocks":0,"value":"104324219","participants":5,"cost":"0"}]]

const results = mergeData(data)

console.log(results)

<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.27.1/ramda.min.js" integrity="sha512-rZHvUXcc1zWKsxm7rJ8lVQuIr1oOmm7cShlvpV0gWf0RvbcJN6x96al/Rp2L2BI4a4ZkT2/YfVe/8YvB2UHzQw==" crossorigin="anonymous"></script>

CodePudding user response：

Vanila JS solution:

const data = [[{"index":320,"blocks":2,"value":"31011784785","participants":1222,"cost":"1286828506"},{"index":319,"blocks":0,"value":"111306385","participants":18,"cost":"0"},{"index":318,"blocks":0,"value":"14550473","participants":10,"cost":"0"}],[{"index":320,"blocks":1,"value":"7089001673","participants":492,"cost":"648196615"},{"index":319,"blocks":0,"value":"13551137","participants":8,"cost":"0"},{"index":318,"blocks":0,"value":"11499815","participants":5,"cost":"0"}],[{"index":320,"blocks":1,"value":"408900161","participants":200,"cost":"648196615"},{"index":319,"blocks":0,"value":"23551231","participants":10,"cost":"0"},{"index":318,"blocks":0,"value":"104324219","participants":5,"cost":"0"}]];


const result = Object.values(data.flat()
  .reduce((acc, { index, value, participants }) => {
    acc[index] ??= { index, value: 0, participants: 0 };
    acc[index].value  = Number(value);
    acc[index].participants  = Number(participants);
  
    return acc;
}, {}));

console.log(result);

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