Total array of object based on another array value

Question

I am trying to create new array of object with total data by year(or any selected key) but, it doesn't work as expected.

const dataArray = [
  {
    "abc": 10,
    "xyz": 20,
    "year": "2021"
  },
  {
    "abc": 20,
    "xyz": 20,
    "year": "2022"
  },
  {
    "abc": 20,
    "xyz": 10,
    "year": "2021"
  },
  {
    "abc": 30,
    "xyz": 10,
    "year": "2022"
  },
  {
    "abc": 20,
    "xyz": 10,
    "year": "2021"
  },
  {
    "abc": 10,
    "xyz": 10,
    "year": "2022"
  }
]
const keys = ["year", "abc", "xyz"];
const cols = ["year"]

//expected
//[{ "abc": total of abc for 2021, "xyz": total of xyz for 2021, "year" "2021"}, { "abc": total of abc for 2022, "xyz": total of xyz for 2022, "year" "2022"}]

const newObject = {};
cols.forEach(col => {
 dataArray.forEach(arr => {
  keys.forEach(key => {
    if(col != key) {
      newObject[key] += col[key]
    }
  })
 })
})

console.log(newObject);

I tried above but doesn't work as expected.

My expectation is:

[
  {
    "abc": "total of abc for 2021",
    "xyz": "total of xyz for 2021",
    "year": "2021"
  },
  {
    "abc": "total of abc for 2022",
    "xyz": "total of xyz for 2022",
    "year": "2022"
  }
]

Nick · Accepted Answer · 2022-06-10 12:55:27Z

4

You can aggregate dataArray using reduce, building an object whose keys are the year values and values are the accumulated abc and xyz values. You can then convert that into your desired array format using Object.values:

const dataArray = [{
    "abc": 10, "xyz": 20, "year": "2021"
  },
  {
    "abc": 20, "xyz": 20, "year": "2022"
  },
  {
    "abc": 20, "xyz": 10, "year": "2021"
  },
  {
    "abc": 30, "xyz": 10, "year": "2022"
  },
  {
    "abc": 20, "xyz": 10, "year": "2021"
  },
  {
    "abc": 10, "xyz": 10, "year": "2022"
  }
]

const keys = ["year", "abc", "xyz"];
const cols = ["year"]

newObject = Object.values(
  dataArray.reduce((acc, obj) => {
    colkey = cols.map(k => obj[k]).join('##')
    if (acc.hasOwnProperty(colkey)) {
      keys.filter(k => !cols.includes(k)).forEach(k => acc[colkey][k] += obj[k])
    } else {
      acc[colkey] = obj
    }
    return acc
  }, {})
);

console.log(newObject);

.as-console-wrapper { max-height: 100% !important }

edited Jun 10, 2022 at 12:55

answered Jun 9, 2022 at 12:51

Nick

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3 Comments

ketan Over a year ago

But, I don't know it's year or month. It should be based on cols array. So, I should iterate over cols before reduce?

ketan Over a year ago

Because if I do that it's not working:

newObject = Object.values(   cols.forEach(col => {       dataArray.reduce((acc, { col, ...rest }) => {       console.log(col);     return acc     });   }, {}) )

Nick Over a year ago

@ketan it wasn't really clear from your question what you wanted, so I wrote an answer based on the data in the question. I think I understand better now, and I've updated my answer to group based on the cols array and sum the values based on the keys in the keys array that are not also in the cols array. Please see my edit...

Xupitan · Accepted Answer · 2022-06-22 07:16:04Z

const dataArray = [
  {
    "abc": 10,
    "xyz": 20,
    "year": "2021"
  },
  {
    "abc": 20,
    "xyz": 20,
    "year": "2022"
  },
  {
    "abc": 20,
    "xyz": 10,
    "year": "2021"
  },
  {
    "abc": 30,
    "xyz": 10,
    "year": "2022"
  },
  {
    "abc": 20,
    "xyz": 10,
    "year": "2021"
  },
  {
    "abc": 10,
    "xyz": 10,
    "year": "2022"
  }
]

const result = dataArray.reduce((res, ele) => {
  let exist = res.find(e => e.year === ele.year)
  if(exist) {
    exist.abc += ele.abc
    exist.xyz += ele.xyz
  } else {
    res = [...res, {...ele}]
  }
  return res
}, [])

// other way
const result1 = Object.values(
  dataArray.reduce((res, {year, ...rest}) => {
    let ele = res[year] ??= {year}
    Object.entries(rest).forEach(([k, v]) => ele[k] = (ele[k] ?? 0)  + v)
    return res
  }, {})
)
console.log(result, result1)

HiddenOne1254 · Accepted Answer · 2022-06-10 13:10:27Z

if you want some different approach

  const dataArray = [
  {
    "abc": 10,
    "xyz": 20,
    "year": "2021"
  },
  {
    "abc": 20,
    "xyz": 20,
    "year": "2022"
  },
  {
    "abc": 20,
    "xyz": 10,
    "year": "2021"
  },
  {
    "abc": 30,
    "xyz": 10,
    "year": "2022"
  },
  {
    "abc": 20,
    "xyz": 10,
    "year": "2021"
  },
  {
    "abc": 10,
    "xyz": 10,
    "year": "2022"
  }
]
let mainObj = {}
dataArray.forEach((el)=>{
    if(!mainObj.hasOwnProperty(el.year)){
        mainObj[el.year] = {}
        mainObj[el.year].abc = el.abc
        mainObj[el.year].xyz = el.xyz
        mainObj[el.year].year = el.year
    }
    else{
        mainObj[el.year].abc = mainObj[el.year].abc + el.abc
        mainObj[el.year].xyz = mainObj[el.year].xyz + el.xyz
        
    }
})
let values = Object.values(mainObj)
console.log(values)

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