data formatting with lodash

Question

suppose i have the following json array:

const input = [
  { "tx_type": "215", "dos": "2019-05-02", "payer": "Cigna", "count": 23 },
  { "tx_type": "215", "dos": "2019-05-02", "payer": "SENIORCARE Plus", "count": 75 },
  { "tx_type": "217", "dos": "2019-05-02", "payer": "Aetna", "count": 2 },
  { "tx_type": "215", "dos": "2019-05-03", "payer": "Aetna", "count": 85 },
  { "tx_type": "215", "dos": "2019-05-03", "payer": "TRICARE", "count": 1 },
  { "tx_type": "215", "dos": "2019-05-03", "payer": "Aetna", "count": 5 },
  { "tx_type": "215", "dos": "2019-05-03", "payer": "Cigna", "count": 11 }
]

which comes out of a postgres 9.2 db, but I am trying to fit the data into a dataviz that expects the data to look like:

[
  {
    "tx_type": "x215",
    "dos": [
      { "date": "2019-05-02", "SENIORCARE Plus": 75, "Cigna": 23 },
      { "date": "2019-05-03", "Aetna": 96, "TRICARE": 1, "Cigna": 11 }
    ],
  },
  {
    "tx_type": "x215",
    "dos": [
      { "date": "2019-05-02", "Aetna": 2 }
    ]
  }
]

i have tried using lodash to group the objects by tx_type using .groupBy("tx_type"), as well as _.chain(input).nest("tx_type").groupBy("dos").value(), as well as filtering by tx_type and then trying to group/ nest...

really, all I am trying to do is filter by tx_type and group the payers and counts by date.

any input would be greatly appreciated. and as much as i want to upgrading to a newer version of postgres isn't really an option..

Answer 1

Group by tx_type and map the groups. To create the dos property, map the items in the group, group them by dos, map the results to convert each row to an object of { data, [payer]:count }, and merge the objects:

const input = [{"tx_type":"215","dos":"2019-05-02","payer":"Cigna","count":23},{"tx_type":"215","dos":"2019-05-02","payer":"SENIORCARE Plus","count":75},{"tx_type":"217","dos":"2019-05-02","payer":"Aetna","count":2},{"tx_type":"215","dos":"2019-05-03","payer":"Aetna","count":85},{"tx_type":"215","dos":"2019-05-03","payer":"TRICARE","count":1},{"tx_type":"215","dos":"2019-05-03","payer":"Aetna","count":5},{"tx_type":"215","dos":"2019-05-03","payer":"Cigna","count":11}]

const result = _(input)
  .groupBy('tx_type')
  .map((dos, tx_type) => ({
    tx_type,
    dos: _(dos)
      .groupBy('dos')
      .map((g, date) => _.merge({}, 
        ..._.map(g, ({ payer, count }) => ({ date,  [payer]: count }))
      ))
      .value()
  }))
  .value()
  
console.log(result)

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