Object assign to update object's nested object

Question

Hi I have a list of objects. I want to create a new instance of these objects to update one value.

const arr = [
  { data: { name: "first", type: "child" } },
  { data: { name: "second", type: "parent" } },
];

I would like to have an array of the same objects, but whose type would be upper case like below:

const arr = [
  { data: { name: "first", type: "CHILD" } },
  { data: { name: "second", type: "PARENT" } },
];

I map this array and return new mapped objects, I can add new prop to an object but I can not find a way to change data.type. Here is my piece of code:

const a = arr.map(e => {
    return Object.assign({},e,{data['type']:'???'}
});

Ran Marciano · Accepted Answer · 2020-11-12 11:52:04Z

3

How about this way?

const arr=[{data:{name:'first',type:'child'}},{data:{name:'second', type:'parent'}}]
const a = arr.map(e => {
  let data = {...e["data"], type: e["data"].type.toUpperCase()};
  return ({...e, data});
});
console.log(a);

edited Nov 12, 2020 at 11:52

answered Nov 12, 2020 at 11:31

Ran Marciano

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1 Comment

anime Over a year ago

with a slight modification it was what I needed, thanks;)

Aadil Mehraj · Accepted Answer · 2020-11-12 15:02:26Z

3

Using map:

const result = data.map(({ data }) => ({ data: { ...data, type: data.type.toUpperCase() }}));

const data = [{data:{name:'first',type:'child'}},{data:{name:'second', type:'parent'}}]

const result = data.map(({ data }) => ({ data: { ...data, type: data.type.toUpperCase() }}));

console.log({result})

edited Nov 12, 2020 at 15:02

answered Nov 12, 2020 at 11:20

Aadil Mehraj

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2 Comments

Aadil Mehraj Over a year ago

Please check the input/output again

Nick Parsons Over a year ago

The objects are supposed to have a data property

Hugh · Accepted Answer · 2023-05-17 13:07:41Z

3

You don't need to use Object.assign:

const arr = [
  { data: { name: "first", type: "child" } },
  { data: { name: "second", type: "parent" } },
];

const a = arr.map(e => ({
    data: {
       name: e.data.name,
       type: e.data.type.toUpperCase()
    }
}))

console.log(a)

edited May 17, 2023 at 13:07

answered Nov 12, 2020 at 11:21

Hugh

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6 Comments

anime Over a year ago

I use object assign because i'm adding some new values to them

Hugh Over a year ago

map will return new objects: developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…

anime Over a year ago

yes and I want new array of objects with 'modified' values. Of course original array has to stay untouched

Hugh Over a year ago

That's the purpose of map. It does exactly what you want to do. Try my code

Arman O Over a year ago

This code will never work. Try to run and you will got TypeError: e.type is undefined

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