How to remove duplicates in array object and apply sum to particular key in javascript

Question

I have a object obj, in which how to remove duplicate in info and apply the sum of quantity qty to key total in javascript. How to remove duplicates in array object and apply sum to particular key in javascript.

function newList (obj){
 return obj.map(i=>({
          ...i,
          total: i.info.map(e => e.qty).reduce((prev, curr) => prev + curr, 0)
 }));
}

var obj =[
 {id:1, info:[{idx:1, qty: 1}, {idx:2, qty: 2},{idx:2, qty: 2}], code: "sample1", total: 1},
 {id:2, info:[{idx:3, qty: 2}, {idx:4, qty: 2}], code: "sample2", total: 2}
]

Expected Output:

[
 {id:1, info:[{idx:1, qty: 1}, {idx:2, qty: 2}], code: "sample1", total: 3},
 {id:2, info:[{idx:3, qty: 2}, {idx:4, qty: 2}], code: "sample2", total: 4}
]

Does this answer your question? [How to get unique values in an array](https://stackoverflow.com/questions/11246758/how-to-get-unique-values-in-an-array) — m02ph3u5, Jun 28 '20 at 13:30
may this help your question https://stackoverflow.com/questions/9229645/remove-duplicate-values-from-js-array — Raghul SK, Jun 28 '20 at 13:32
Does this answer your question? [Checking for duplicate strings in JavaScript array](https://stackoverflow.com/questions/49215358/checking-for-duplicate-strings-in-javascript-array) — Mike Ezzati, Jun 28 '20 at 13:36
I think that the totals you show in the expected result do not add the original value of the total. Can you confirm it please. I think the totals should be 4 and 6 — Mario, Jun 28 '20 at 14:00

score 0 · Answer 1 · answered Jun 28 '20 at 13:41

You can make use of reduce and Map(to unique the rows):

var obj =[
 {id:1, info:[{idx:1, qty: 1}, {idx:2, qty: 2},{idx:2, qty: 2}], code: "sample1", total: 1},
 {id:2, info:[{idx:3, qty: 2}, {idx:4, qty: 2}], code: "sample2", total: 2}
];

var result = obj.reduce((acc, elem)=>{
    elem.info = [...new Map(elem.info.map(i=>[i.idx, i])).values()];
    elem.total = elem.info.reduce((sum, {qty})=>sum+qty,0);
    acc = [...acc, elem];
    return acc;
},[]);

console.log(result);

score 0 · Answer 2 · edited Jun 28 '20 at 14:05

Please try the following example, although my result differs from the totals that show as the expected result. Try it please

const obj = [
  {
    id: 1,
    info: [
      { idx: 1, qty: 1 },
      { idx: 2, qty: 2 },
      { idx: 2, qty: 2 },
    ],
    code: "sample1",
    total: 1,
  },
  {
    id: 2,
    info: [
      { idx: 3, qty: 2 },
      { idx: 4, qty: 2 },
    ],
    code: "sample2",
    total: 2,
  },
];

let output = obj.map((entry) => {
  return {
    ...entry,
    info: entry.info.reduce((prev, curr) => {
      const item = prev.find(
        (element) => element.idx === curr.idx && element.qty == curr.qty
      );

      if (!item) {
        prev = [...prev, curr];
      }

      return prev;
    }, []),
  };
});

output = output.map((entry) => {
  return {
    ...entry,
    total: entry.total + entry.info.reduce((prev, curr) => prev + curr.qty, 0),
  };
});

console.dir(output, { depth: null, color: true });

See

score 0 · Answer 3 · answered Jun 28 '20 at 14:09

function newList(obj) {
    return obj.map(i => ({
        ...i,
        ...reduceInfo(i.info)
    }));

}

function reduceInfo(array) {
    return array.reduce((a, c) => {
        a.info = a.info || [];
        a.total = a.total || 0;
        if (!a.info.some(element => c.idx === element.idx && c.qty === element.qty)) {
            a.info.push(c);
            a.total = a.total + c.qty;
        }
        return a;

    }, {});
}

var obj = [
    { id: 1, info: [{ idx: 1, qty: 1 }, { idx: 2, qty: 2 }, { idx: 2, qty: 2 }], code: "sample1", total: 1 },
    { id: 2, info: [{ idx: 3, qty: 2 }, { idx: 4, qty: 2 }], code: "sample2", total: 2 }
]

console.log(JSON.stringify(newList(obj)));

How to remove duplicates in array object and apply sum to particular key in javascript

3 Answers3