CODEWITHSUNDEEP
javascriptarraysreactjs
MrVerticalStack
MrVerticalStack

Reputation: 47

React looping and creating new array with nested objects

I have an array of documents:

    [{
      "name": "AAPL",
      "ownerTotals": {uid: "xxx", totaledAmount: 140 }, {uid: "yyy", totaledAmount: 10}
    },
    {
      "name": "TSLA",
      "ownerTotals": {uid: "xxx", totaledAmount: 11 }, {uid: "yyy", totaledAmount: 2}
    }]

and an array of owners:

{uid: "xxx"}, {uid: "yyy"}

I'm trying to create a new/(update) the owners object with a nested object that contains the positions they own. so I want to update owners to this format:

    [{uid: "xxx", "positions": [{name: "AAPL", totaledAmount: 140 },{name: "TSLA", totaledAmount: 11}] },
    {uid: "yyy", "positions": [{name: "AAPL", totaledAmount: 10 },{name: "TSLA", totaledAmount: 2}] }]

what's the best way to achieve this?

I was trying for something along the lines of

owners.forEach((owner) => {
        documents.forEach((document) => {
           document.ownerTotals.forEach((ownerTotal) => {
                if (ownerTotal.uid === owner.uid) {

                 }
             }
        })
     }
})

Not really sure what to do at the heart of each loop, and not even sure if ForEach is the most method way for this...I'm using modern react with hooks.

Upvotes: 0

Views: 44

Answers (2)

Radu Diță
Radu Diță

Reputation: 14171

You can use reduce to group positions by userid.

const positions =  [{
      "name": "AAPL",
      "ownerTotals": {uid: "xxx", totaledAmount: 140 }, {uid: "yyy", totaledAmount: 10}
    },
    {
      "name": "TSLA",
      "ownerTotals": {uid: "xxx", totaledAmount: 11 }, {uid: "yyy", totaledAmount: 2}
    }]

const posByUid = positions.reduce((acc, current) => {
 const name = current.name
 current.positions.forEach(position => {
   if (!acc[position.uid]) {
    acc[position.uid] = []
   }

   acc[position.uid] = {name, totaledAmount: position.totaledAmount}
 })
 return acc
}, {})

Upvotes: 1

mgm793
mgm793

Reputation: 2066

You can do something like this:

const documents = [
  {
    name: "AAPL",
    ownerTotals: [
      { uid: "xxx", totaledAmount: 140 },
      { uid: "yyy", totaledAmount: 10 }
    ]
  },
  {
    name: "TSLA",
    ownerTotals: [
      { uid: "xxx", totaledAmount: 11 },
      { uid: "yyy", totaledAmount: 2 }
    ]
  }
];

const owners = [{ uid: "xxx" }, { uid: "yyy" }];

const res = owners.map(({ uid }) => {
  let ownedDocuments = [];
  documents.forEach((doc) => {
    let docFound = doc.ownerTotals.find(({ uid: docUid }) => docUid === uid);
    if (docFound) {
      ownedDocuments.push({
        name: doc.name,
        totaledAmount: docFound.totaledAmount
      });
    }
  });
  return {
    uid,
    positions: ownedDocuments
  };
});

console.log(res);

Upvotes: 2

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