Group By, and Sum, and Generate an Object for Each Array in JavaScript

How to group by and sum an array of objects?

You can loop and sum it up

var array = [  { Id: "001", qty: 1 },   { Id: "002", qty: 2 },   { Id: "001", qty: 2 },   { Id: "003", qty: 4 }];
var result = [];array.reduce(function(res, value) {  if (!res[value.Id]) {    res[value.Id] = { Id: value.Id, qty: 0 };    result.push(res[value.Id])  }  res[value.Id].qty += value.qty;  return res;}, {});
console.log(result)

Group by, and sum, and generate an object for each array in JavaScript

You can try this:

const result = Object.values(data.reduce((r, o) => (r[o.id]
  ? (r[o.id].total += o.total)
  : (r[o.id] = {...o}), r), {}));

how to group and sum data in foreach javascript

you can use reduce usually for these grouping problems. I'm taking the combination of code and date to group. something like "8|2022-03-24".

This is how the intermediate object will look like

{
  8|2022-03-24: {
    code: 8,
    date: "2022-03-24",
    total: 12
  },
  8|2022-03-25: {
    code: 8,
    date: "2022-03-25",
    total: 2
  },
  9|2022-03-24: {
    code: 9,
    date: "2022-03-24",
    total: 4
  },
  9|2022-03-25: {
    code: 9,
    date: "2022-03-25",
    total: 3
  }
}

From that object I'm taking the values using Object.values

const data = [
{code: 8, date:"2022-03-24", total:4},
{code: 8, date:"2022-03-24", total:8},
{code: 8, date:"2022-03-25", total:2},
{code: 9, date:"2022-03-24", total:4},
{code: 9, date:"2022-03-25", total:2},
{code: 9, date:"2022-03-25", total:1},]

let grouped = Object.values(data.reduce((acc,{code,date,total})=>{
    acc[code+'|'+date] = acc[code+'|'+date] || {code,date,total:0}
  acc[code+'|'+date].total+=total
  return acc;
},{}))

console.log(grouped)

Javascript array of objects group and sum items

This works fine

Object.values(
  cars.reduce((agg, car) => {
    if (agg[car.make] === undefined) agg[car.make] = { make: car.make, sumQuantity: 0 }
    agg[car.make].sumQuantity += +car.quantity
    return agg
  }, {})
)

How to group by and sum an array of objects javascript?

You group the array into an object, where the keys are concatenation of available and id properties and finally transform the object back to an array using Object.values.

const 
  array = [
    { data: { qty: "5", toy: { id: 3 }, available: "yes" } },
    { data: { qty: "5", toy: { id: 10 }, available: "no" } },
    { data: { qty: "59", toy: { id: 10 }, available: "yes" } },
    { data: { qty: "5", toy: { id: 3 }, available: "yes" } },
  ],
  result = Object.values(
    array.reduce((r, { data }) => {
      const k = data.available + data.toy.id;
      if (r[k]) {
        r[k].data.qty = String(Number(r[k].data.qty) + Number(data.qty));
      } else {
        r[k] = { data };
      }
      return r;
    }, {})
  );

console.log(result);

GroupBy array of objects to new array and sum value

Looking at your initial array and the output you wanted to get, below are the examples that result in exactly the same structure as per your question - an array of arrays of objects

One way with find & for of loop:

let arr = [
 {
    "year": "202003",
    "cost": 11194.55,
    "type": "A"
  },
  {
    "year": "202003",
    "cost": 60.2,
    "type": "B"
  },
  {
    "year": "202003",
    "cost": 747.12,
    "type": "C"
  },
  {
    "year": "202003",
    "cost": 747.12,
    "type": "D"
  },
  {
    "year": "202004",
    "cost": 747.12,
    "type": "D"
  },
  {
    "year": "202003",
    "cost": 4674.59,
    "type": "D"
  }
]

let sortedArray = []
for (let [index, el] of arr.entries()) {
  if(sortedArray.find(elInner => (elInner[0].type === el.type && elInner[0].year !== el.year))) {
    sortedArray.find(elInner => elInner[0].type === el.type).push(arr[index])
  }else if (sortedArray.find(elInner => (elInner[0].type === el.type && elInner[0].year == el.year))) {
    sortedArray.find(elInner => (elInner[0].type === el.type && elInner[0].year == el.year))[0].cost += arr[index].cost
  }else {
    sortedArray.push([el])
  }
}
console.log(sortedArray)

how to group by and total sum array of object in javascript?

You could try something like this

const output = Object.entries(groupByMonth).map(([time, datapoints]) => {
  const codes = {}
  const allTasks = datapoints.flatMap(point => point.task)
  for (const { code, value } of allTasks) {
    codes[code] = (codes[code] || 0) + value
  }
  return {
    time,
    tasks: Object.entries(codes).map(([code, value]) => ({ code, value }))
  }
}

Though one downside is that the time complexity isn't perfect because of the structure of the data