CODEWITHSUNDEEP
javascriptarraysobject
Chandan Singh
Chandan Singh

Reputation: 41

How can I multiply to each array of object values with a constant?

How can I multiple each element of array of object value with a constant?

Input

[{"key":usd, "value":20 }, {"key":aed, "value":50 },{"inr":usd, "value":30 },{"key":usd, "value":40 }]

Output 

[{"key":usd, "value":40 }, {"key":aed, "value":100 },{"inr":usd, "value":60 },{"key":usd, "value":80 }]

Upvotes: 1

Views: 1361

Answers (5)

iambinodstha
iambinodstha

Reputation: 1007

without mutating your original array. feel free to comment if you don't understand.

let someArray = [{"key":"usd", "value":20 }, {"key":"aed", "value":50 },{"inr":"usd", "value":30 },{"key":"usd", "value":40 }]

let result = someArray.map(data=>{
return {...data, value: data.value*2}
})

console.log(result);

Upvotes: 1

Harshwardhan Sharma
Harshwardhan Sharma

Reputation: 261

const arr = [{"key":"usd", "value":20 }, {"key":"aed", "value":50 },{"inr":"usd", "value":30 },{"key":"usd", "value":40 }];
arr.map(function(value,key){
    arr[key].value *=2;
});
console.log(arr);

Output

[{"key":"usd", "value":40 }, {"key":"aed", "value":100 },{"inr":"usd", "value":60 },{"key":"usd", "value":80 }];

Upvotes: 1

Jack Bashford
Jack Bashford

Reputation: 44125

You can just use Array.prototype.map() and ES6 arrow syntax like this:

const arr = [{
  "key": "usd",
  "value": 20
}, {
  "key": "aed",
  "value": 50
}, {
  "inr": "usd",
  "value": 30
}, {
  "key": "usd",
  "value": 40
}];
const value = 2;
const result = arr.map(e => {
  e.value *= value;
  return e;
});
console.log(result);

And if you want to, you can just return the doubled values like this, by returning the doubles value of e.value:

const arr = [{
  "key": "usd",
  "value": 20
}, {
  "key": "aed",
  "value": 50
}, {
  "inr": "usd",
  "value": 30
}, {
  "key": "usd",
  "value": 40
}];
const value = 2;
const result = arr.map(e => e.value *= value);
console.log(result);

Upvotes: 0

Mustehssun Iqbal
Mustehssun Iqbal

Reputation: 566

const arr = [{"key":"usd", "value":20 }, {"key":"aed", "value":50 },{"inr":"usd", "value":30 },{"key":"usd", "value":40 }];

const modifiedArr = arr.map(item => {
    var modifiedItem = Object.assign({}, item);
    modifiedItem.value *= 2;

    return modifiedItem;
});

console.log(arr);
console.log(modifiedArr);

Edit: used modifiedItem for immutability as pointed out by @UncleDave

Upvotes: 2

amirhosein
amirhosein

Reputation: 921

you can use this sample function for this input type,in other case you have to change this function,pass your object as input: 

valueChanger(input){
    var tx = []
    for(var x = 0;x < Object.keys(input).length ; x++){
        var obj = {}
        obj['key'] = input[x]['key'] // do anything with key if you want in here
        obj['value'] = input[x]['value']*2 
        tx.push(obj)
    }
    return tx
}

Upvotes: 0

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