Replace key value inside array of object with another object with same key

Question

Suppose I have an array of object:

const purchaseDetails = [
  {
      amount: '4567',
      purchaseOrder: 'B234',
      purchaseDate: '10/12/2020',
      someRandom1: '123',
      someRandom2: '345'
   },
   {
      amount: '4567',
      purchaseOrder: 'B234',
      purchaseDate: '10/12/2020',
      someRandom1: '678',
      someRandom2: '987'
    }
]

and another object as:

const toReplace = {
      amount: '1211',
      purchaseOrder: 'A123',
      purchaseDate: '12/30/2020',
      vat: '123',
 }

I want to replace value of purchaseDetails with toReplace value

O/p as:

const purchaseDetails = [
    {
         amount: '1211',
         purchaseOrder: 'A123',
         purchaseDate: '12/30/2020',
         vat: '123',
         someRandom1: '123',
         someRandom2: '345'
     },
     {
         amount: '1211',
         purchaseOrder: 'A123',
         purchaseDate: '12/30/2020',
         vat: '123',
         someRandom1: '678',
         someRandom2: '987'
      }
  ]

For this i tried as:

purchaseDetails.forEach(element => {
  element.amount=toReplace.amount,element.purchaseOrder=toReplace.purchaseOrder,
   element.purchaseDate=toReplace.purchaseDate,element.tax=toReplace.tax
});

But it doesnot replace the value...i tried with single value as well but it's not working.

As per provided solution it was assignment issue.

But the second solution provided, when I try:

purchaseDetails.forEach(element => {
        element = {...element, ...avacado}
        console.log(element)
});

On console.log(element), it shows element with value changed but console.log(purchaseDetails) value doesnot change.

== is used for comparisons. Use = for assignments. You should be able to do element = {...element, ...toReplace}. — user5734311
– user5734311, Commented Mar 10, 2021 at 11:47
Thank you..= assignment was the issue but your second solution looks much better but while I'm trying as below it doesnot work. Could you please guide? purchaseDetails.forEach(element => { element = {...element, ...toReplace} }); But it doesn't work.....is there something wrong that I am doing? — Siva Pradhan
– Siva Pradhan, Commented Mar 10, 2021 at 11:55
Yeah, sorry, that won't work here. However you can do Object.assign(element, toReplace); instead. — user5734311
– user5734311, Commented Mar 10, 2021 at 12:04
Thank you so much for the help....could you please provide it in the answer section so I could accept it. — Siva Pradhan
– Siva Pradhan, Commented Mar 10, 2021 at 12:07

connexo · Accepted Answer · 2021-03-10 12:38:10Z

1

If you instead declare purchaseDetails via let (thus allowing reassigning the result of map call later), you can use Array.prototype.map:

let purchaseDetails = [{
    amount: '4567',
    purchaseOrder: 'B234',
    purchaseDate: '10/12/2020',
    someRandom1: '123',
    someRandom2: '345'
  },
  {
    amount: '4567',
    purchaseOrder: 'B234',
    purchaseDate: '10/12/2020',
    someRandom1: '678',
    someRandom2: '987'
  }
]

const toReplace = {
  amount: '1211',
  purchaseOrder: 'A123',
  purchaseDate: '12/30/2020',
  vat: '123',
}

purchaseDetails = purchaseDetails.map(obj => ({ ...obj, ...toReplace }));

console.log(purchaseDetails);

answered Mar 10, 2021 at 12:38

connexo

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