How to group and merge array entries and to sum-up values on multiple common (but not all) keys?-CodePudding

This thread had multiple approaches for summing values by common key, and one had a method to group by all common keys. I am looking for a more granular and controlled grouping. My data example is the following:

const arr = [
{'ID':'1','Parent':'1','Member': '1','Code': '123','Subject': 'Org A','value': 0.3},
{'ID':'2','Parent':'1','Member': '1','Code': '124','Subject': 'Org A','value': 0.25},
{'ID':'3','Parent':'1','Member': '1','Code': '123','Subject': 'Org B','value': 0.45},
{'ID':'4','Parent':'1','Member': '2','Code': '125','Subject': 'Org A','value': 0.8},
{'ID':'5','Parent':'1','Member': '2','Code': '211','Subject': 'Org C','value': 0.3},
{'ID':'6','Parent':'1','Member': '3','Code': '221','Subject': 'Org B','value': 0.3},
{'ID':'7','Parent':'1','Member': '3','Code': '221','Subject': 'Org C','value': 0.25},
{'ID':'8','Parent':'1','Member': '3','Code': '234','Subject': 'Org A','value': 0.45},
{'ID':'9','Parent':'1','Member': '4','Code': '123','Subject': 'Org A','value': 0.8},
{'ID':'10','Parent':'2','Member': '5','Code': '123','Subject': 'Org D','value': 0.3},
{'ID':'11','Parent':'2','Member': '5','Code': '123','Subject': 'Org E','value': 0.3},
{'ID':'12','Parent':'2','Member': '6','Code': '125','Subject': 'Org E','value': 0.25},
{'ID':'13','Parent':'2','Member': '6','Code': '211','Subject': 'Org F','value': 0.45},
{'ID':'14','Parent':'2','Member': '6','Code': '221','Subject': 'Org F','value': 0.8},
{'ID':'15','Parent':'2','Member': '6','Code': '123','Subject': 'Org G','value': 0.3},
{'ID':'16','Parent':'3','Member': '7','Code': '124','Subject': 'Org H','value': 0.3},
{'ID':'17','Parent':'3','Member': '8','Code': '124','Subject': 'Org H','value': 0.25},
{'ID':'18','Parent':'3','Member': '9','Code': '123','Subject': 'Org I','value': 0.45},
{'ID':'19','Parent':'3','Member': '10','Code': '123','Subject': 'Org J','value': 0.8},
{'ID':'20','Parent':'3','Member': '10','Code': '211','Subject': 'Org I','value': 0.3},
{'ID':'21','Parent':'4','Member': '11','Code': '221','Subject': 'Org K','value': 0.3},
{'ID':'22','Parent':'4','Member': '11','Code': '234','Subject': 'Org K','value': 0.25},
{'ID':'23','Parent':'4','Member': '12','Code': '234','Subject': 'Org K','value': 0.45},
{'ID':'24','Parent':'4','Member': '12','Code': '123','Subject': 'Org L','value': 0.8},
{'ID':'25','Parent':'4','Member': '13','Code': '211','Subject': 'Org M','value': 0.3}
];

The solutions from the other thread either group by 1 set column:

// Group by 1 column //

const summed = arr.reduce((acc, cur) => {
  const item = acc.length > 0 && acc.find(({
    Code
  }) => Code === cur.Code)
  if (item) {
    item.value  = cur.value
  } else acc.push({Code:cur.Code,value:cur.value});
  return acc
}, [])
console.log(arr); // not modified
console.log(summed)

Or by all common values

// Group by multiple columns //

const res = Array.from(arr.reduce((acc, {value, ...r}) => {
  const key = JSON.stringify(r);
  const current = acc.get(key) || {...r, value: 0};  
  return acc.set(key, {...current, value: current.value   value});
}, new Map).values());
console.log(res);

I am trying to group by Parent and Code to sum the value.

CodePudding user response：

Just test both properties in the find() callback, and add both to the new object when pushing into acc.

const arr = [
{'ID':'1','Parent':'1','Member': '1','Code': '123','Subject': 'Org A','value': 0.3},
{'ID':'2','Parent':'1','Member': '1','Code': '124','Subject': 'Org A','value': 0.25},
{'ID':'3','Parent':'1','Member': '1','Code': '123','Subject': 'Org B','value': 0.45},
{'ID':'4','Parent':'1','Member': '2','Code': '125','Subject': 'Org A','value': 0.8},
{'ID':'5','Parent':'1','Member': '2','Code': '211','Subject': 'Org C','value': 0.3},
{'ID':'6','Parent':'1','Member': '3','Code': '221','Subject': 'Org B','value': 0.3},
{'ID':'7','Parent':'1','Member': '3','Code': '221','Subject': 'Org C','value': 0.25},
{'ID':'8','Parent':'1','Member': '3','Code': '234','Subject': 'Org A','value': 0.45},
{'ID':'9','Parent':'1','Member': '4','Code': '123','Subject': 'Org A','value': 0.8},
{'ID':'10','Parent':'2','Member': '5','Code': '123','Subject': 'Org D','value': 0.3},
{'ID':'11','Parent':'2','Member': '5','Code': '123','Subject': 'Org E','value': 0.3},
{'ID':'12','Parent':'2','Member': '6','Code': '125','Subject': 'Org E','value': 0.25},
{'ID':'13','Parent':'2','Member': '6','Code': '211','Subject': 'Org F','value': 0.45},
{'ID':'14','Parent':'2','Member': '6','Code': '221','Subject': 'Org F','value': 0.8},
{'ID':'15','Parent':'2','Member': '6','Code': '123','Subject': 'Org G','value': 0.3},
{'ID':'16','Parent':'3','Member': '7','Code': '124','Subject': 'Org H','value': 0.3},
{'ID':'17','Parent':'3','Member': '8','Code': '124','Subject': 'Org H','value': 0.25},
{'ID':'18','Parent':'3','Member': '9','Code': '123','Subject': 'Org I','value': 0.45},
{'ID':'19','Parent':'3','Member': '10','Code': '123','Subject': 'Org J','value': 0.8},
{'ID':'20','Parent':'3','Member': '10','Code': '211','Subject': 'Org I','value': 0.3},
{'ID':'21','Parent':'4','Member': '11','Code': '221','Subject': 'Org K','value': 0.3},
{'ID':'22','Parent':'4','Member': '11','Code': '234','Subject': 'Org K','value': 0.25},
{'ID':'23','Parent':'4','Member': '12','Code': '234','Subject': 'Org K','value': 0.45},
{'ID':'24','Parent':'4','Member': '12','Code': '123','Subject': 'Org L','value': 0.8},
{'ID':'25','Parent':'4','Member': '13','Code': '211','Subject': 'Org M','value': 0.3}
];

const summed = arr.reduce((acc, cur) => {
  const item = acc.length > 0 && acc.find(({
    Code, Parent
  }) => Code === cur.Code && Parent == cur.Parent)
  if (item) {
    item.value  = cur.value
  } else acc.push({
    Code: cur.Code,
    Parent: cur.Parent,
    value: cur.value
  });
  return acc
}, [])
console.log(arr); // not modified
console.log(summed)

CodePudding user response：

From my above comment ...

The OP might find an answer in the entirely generic implemented approach posted as a solution to this recently asked question ... "How, from an array of objects, does one group, merge and aggregate values, each task by one or more different property-names / object-keys?"

function groupMergeAndAggregateGenerically(collector, item) {
  const {
    createKey, createMerger, aggregate,
    lookup, result = [],
  } = collector;

  const key = createKey(item);
  let merger = lookup.get(key) ?? null;

  if (merger === null) {
    merger = createMerger(item);

    lookup.set(key, merger);
    result.push(merger);
  }
  aggregate(merger, item);

  return collector;
}

const arr = [
  { 'ID':'1','Parent':'1','Member': '1','Code': '123','Subject': 'Org A','value': 0.3 },
  { 'ID':'2','Parent':'1','Member': '1','Code': '124','Subject': 'Org A','value': 0.25 },
  { 'ID':'3','Parent':'1','Member': '1','Code': '123','Subject': 'Org B','value': 0.45 },
  { 'ID':'4','Parent':'1','Member': '2','Code': '125','Subject': 'Org A','value': 0.8 },
  { 'ID':'5','Parent':'1','Member': '2','Code': '211','Subject': 'Org C','value': 0.3 },
  { 'ID':'6','Parent':'1','Member': '3','Code': '221','Subject': 'Org B','value': 0.3 },
  { 'ID':'7','Parent':'1','Member': '3','Code': '221','Subject': 'Org C','value': 0.25 },
  { 'ID':'8','Parent':'1','Member': '3','Code': '234','Subject': 'Org A','value': 0.45 },
  { 'ID':'9','Parent':'1','Member': '4','Code': '123','Subject': 'Org A','value': 0.8 },
  { 'ID':'10','Parent':'2','Member': '5','Code': '123','Subject': 'Org D','value': 0.3 },
  { 'ID':'11','Parent':'2','Member': '5','Code': '123','Subject': 'Org E','value': 0.3 },
  { 'ID':'12','Parent':'2','Member': '6','Code': '125','Subject': 'Org E','value': 0.25 },
  { 'ID':'13','Parent':'2','Member': '6','Code': '211','Subject': 'Org F','value': 0.45 },
  { 'ID':'14','Parent':'2','Member': '6','Code': '221','Subject': 'Org F','value': 0.8 },
  { 'ID':'15','Parent':'2','Member': '6','Code': '123','Subject': 'Org G','value': 0.3 },
  { 'ID':'16','Parent':'3','Member': '7','Code': '124','Subject': 'Org H','value': 0.3 },
  { 'ID':'17','Parent':'3','Member': '8','Code': '124','Subject': 'Org H','value': 0.25 },
  { 'ID':'18','Parent':'3','Member': '9','Code': '123','Subject': 'Org I','value': 0.45 },
  { 'ID':'19','Parent':'3','Member': '10','Code': '123','Subject': 'Org J','value': 0.8 },
  { 'ID':'20','Parent':'3','Member': '10','Code': '211','Subject': 'Org I','value': 0.3 },
  { 'ID':'21','Parent':'4','Member': '11','Code': '221','Subject': 'Org K','value': 0.3 },
  { 'ID':'22','Parent':'4','Member': '11','Code': '234','Subject': 'Org K','value': 0.25 },
  { 'ID':'23','Parent':'4','Member': '12','Code': '234','Subject': 'Org K','value': 0.45 },
  { 'ID':'24','Parent':'4','Member': '12','Code': '123','Subject': 'Org L','value': 0.8 },
  { 'ID':'25','Parent':'4','Member': '13','Code': '211','Subject': 'Org M','value': 0.3 },
];

const { result: mergedData } = arr
  .reduce(groupMergeAndAggregateGenerically, {
    // OP: "I am trying to group by Parent and Code ..."
    createKey: ({ Parent, Code }) => [Parent, Code].join('_'),
    createMerger: ({ Parent, Code }) => ({ Parent, Code, value: 0 }),
    // OP: "[and] ... to sum the value."
    aggregate: (merger, { value }) => merger.value  = value,
    lookup: new Map,
    result: [],      
  });

console.log({ mergedData });

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