How to add index values of array in object to a key

Question

I have an object in variable info as :

0: {ProId: "Space", Name: "cake", Quantity: 1}
1: {ProId: "new", Name: "walk", Quantity: 1}

I am trying to change the Quantity value to it's index+1 for each index ,

I have tried to have a static value as:

  for (var key in obj){
    var value= obj[key];
    value['Quantity'] = 5;
  }

Expected O/p:

console.log(info)
    0: {ProId: "Space", Name: "cake", Quantity: 1}
    1: {ProId: "new", Name: "walk", Quantity: 2}
    2: {............................Quantity: 3}.....

But May I know how can I have the Quantity value as above mentioned

You'd be better using an array to store these as there's no guarantee of object ordering being consistent. — net.uk.sweet
– net.uk.sweet, Commented Feb 27, 2020 at 13:11
I'm probably guessing it here but I believe info is an Array as console.log on an array is formatted the way author has formatted on his post @Codenewbie what is the result of console.log(Array.isArray(info)) ? — vidu.sh
– vidu.sh, Commented Feb 27, 2020 at 13:29
So, your variable info is indeed an Array. You can have a look at the solutions below suggesting to loop through it with Array.forEach or Array.map — vidu.sh
– vidu.sh, Commented Feb 27, 2020 at 13:40

Nina Scholz · Accepted Answer · 2022-01-14 10:40:11Z

Some hints:

Take an array instead of an object, if you need an easy iterable data structure. This gives control over the iteration order, too.
Use numbers for numeric values. If you need later a (formatted) string apply toString to it.

For getting a new value of a property, you could mutate the given data.

Using:

Array#forEach for visiting all items of the array,
an arrow function, a short form of a function.

var array = [{ ProId: "Space", Name: "cake", Quantity: "1" }, { ProId: "new", Name: "walk", Quantity: "1" }];

array.forEach((object, i) => object.Quantity = i + 1);

console.log(array);

Or get new objects by mapping the array.

Using:

Array#map for getting a new array,
spread syntax ... for taking all properties of an object into a new object

var array = [{ ProId: "Space", Name: "cake", Quantity: "1" }, { ProId: "new", Name: "walk", Quantity: "1" }],
    newArray = array.map((object, i) => ({ ...object, Quantity: i + 1 }));

console.log(newArray);

palaѕн · Accepted Answer · 2020-02-27 13:29:29Z

2

You can map the array and return a new array but merging the old object with new object with updated Quantity value like:

const data = [{ProId: "Space", Name: "cake", Quantity: "1"}, {ProId: "new", Name: "walk", Quantity: "1"}],
  updatedData = data.map((x, i)=> ({...x, Quantity: ++i}));
 
console.log(updatedData)

.as-console-wrapper { max-height: 100% !important; top: 0; }

A simple example of updating an object key value (which is done here inside the map() method) is like:

let obj = { a: 0, b: 0};
let newObj = { ...obj, a: 1 };

console.log( newObj )

edited Feb 27, 2020 at 13:29

answered Feb 27, 2020 at 13:18

palaѕн

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3 Comments

jonatjano Over a year ago

can you try giving some explanations of what's going on please

KcH Over a year ago

But I have the data as I mentioned , not the above way you mentioned

palaѕн Over a year ago

How you have the data like? Can you share the actual data format, not the console log view?

Ioannis Potouridis · Accepted Answer · 2020-02-27 13:20:47Z

1

One way is to map your current array.

const info2 = info.map((product, index) => ({ ...product, Quantity: index + 1 }));

In case you want Quantity as a string do this Quantity: index + 1 + '', or Quantity: (index + 1).toString(). Whatever suits you.

answered Feb 27, 2020 at 13:20

Ioannis Potouridis

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Comments

Manikant Gautam · Accepted Answer · 2020-02-27 13:24:54Z

1

Use forEach with index and add Quantity at certain index + index. And use toString() method as you want to have values in String format.

var obj = [{ProId: "Space", Name: "cake", Quantity: "1"}, {ProId: "new", Name: "walk", Quantity: "1"}]
obj.forEach(function(el,idx){
  el.Quantity=(idx+parseInt(el.Quantity)).toString()
})
console.log(obj);

edited Feb 27, 2020 at 13:24

answered Feb 27, 2020 at 13:14

Manikant Gautam

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Comments

AyushKatiyar · Accepted Answer · 2020-02-27 13:26:07Z

1

Try using:

let obj = {
 '0': {ProId: "Space", Name: "cake", Quantity: "1"},
 '1': {ProId: "new", Name: "walk", Quantity: "1"}
}
for(key in obj) {
   let qty = String(Number(obj[key]['Quantity'])+Number(key))
   obj[key]['Quantity'] = qrt;
}

edited Feb 27, 2020 at 13:26

answered Feb 27, 2020 at 13:19

AyushKatiyar

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Comments

Ali Rezayi · Accepted Answer · 2020-02-27 13:29:08Z

1

You can also try this:

let info = {
  0: {
    ProId: "Space",
    Name: "cake",
    Quantity: "1"
  },
  1: {
    ProId: "new",
    Name: "walk",
    Quantity: "1"
  }
}

let index = 1;
Object.values(info).map(function(val) {
  val.Quantity = index;
  index++;
});

console.log(info);

answered Feb 27, 2020 at 13:29

Ali Rezayi

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Comments

Fagner Sales · Accepted Answer · 2020-02-27 14:02:16Z

I made it in the case you are using just the object, without set up as an array.


let info = {
    0: { ProId: "Space", Name: "cake", Quantity: "1" },
    1: { ProId: "new", Name: "walk", Quantity: "2" },
    2: { ProId: "foo", Name: "bar", Quantity: "3" }
}

function incrementQuantify(obj) {
    let _newInfo = {};

    for (const key of Object.keys(obj)) {
        info[key].Quantity = parseInt(info[key].Quantity, 10) + 1;
        _newInfo[key] = info[key];
    }

    return _newInfo;
}
/*
{
  '0': { ProId: 'Space', Name: 'cake', Quantity: 2 },
  '1': { ProId: 'new', Name: 'walk', Quantity: 3 },
  '2': { ProId: 'foo', Name: 'bar', Quantity: 4 }
}
*/
console.log(incrementQuantify(info));

Shorter way:

let info = { 0: { ProId: "Space", Name: "cake", Quantity: "1" }, 1: { ProId: "new", Name: "walk", Quantity: "2" }, 2: { ProId: "foo", Name: "bar", Quantity: "3" } }
for (const key of Object.keys(info)) info[key].Quantity = parseInt(info[key].Quantity, 10) + 1;
console.log(info);

edit: I already made an way to work with arrays too!

let info = [
    { ProId: "Space", Name: "cake", Quantity: "1" },
    { ProId: "new", Name: "walk", Quantity: "2" },
    { ProId: "foo", Name: "bar", Quantity: "3" }
]

function incrementQuantify(obj) {
    let newObj = obj;
    newObj.Quantity = parseInt(obj.Quantity, 10) + 1;
    return newObj;
}
info.map(incrementQuantify);
/*
[
  { ProId: 'Space', Name: 'cake', Quantity: 2 },
  { ProId: 'new', Name: 'walk', Quantity: 3 },
  { ProId: 'foo', Name: 'bar', Quantity: 4 }
]
*/
console.log(info);

Shorter way:

let info = [ { ProId: "Space", Name: "cake", Quantity: "1" }, { ProId: "new", Name: "walk", Quantity: "2" }, { ProId: "foo", Name: "bar", Quantity: "3" } ]; info.map(o => o.Quantity = parseInt(o.Quantity, 10) + 1);
console.log(info);

Hope it helps!

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