How to add a new key value pair in existing JSON object using JavaScript?

Question

var json = {
    "workbookInformation": {
        "version": "9.1",
        "source-platform": "win"
    },
    "datasources1": {
        ...
    },
    "datasources2": {
        ...
    }
}

I need to add new key pair under workbookInformation like

var json={
    "workbookInformation": {
         "version": "9.1",
         "source-platform": "win",
         "new_key":"new_value"
    },
    "datasources1": {
        ...
    },
    "datasources2": {
        ...
    }
}

json['new_key'] = 'new_value'; adds the new key but I want it under "workbookInformation"

json.workbookInformation['new_key'] = 'new_value' this should do — Ajay Narain Mathur
– Ajay Narain Mathur, Commented Jan 18, 2017 at 5:46
FYI, that's not JSON, that's a plain ol' javscript object - JSON is a string, you'd have one heck of a time trying to add a new key to JSON, whoa nelly — Jaromanda X
– Jaromanda X, Commented Jan 18, 2017 at 5:46

Arif H-Shigri · Accepted Answer · 2017-01-18 07:01:46Z

43

There are two ways for adding new key value pair to Json Object in JS

var jsObj = {
    "workbookInformation": {
        "version": "9.1",
        "source-platform": "win"
    },
    "datasources1": {

    },
    "datasources2": {

    }
}

1.Add New Property using dot(.)

jsObj.workbookInformation.NewPropertyName ="Value of New Property";

2.Add New Property specifying index like in an arrays .

jsObj["workbookInformation"]["NewPropertyName"] ="Value of New Property";

Finally

 json = JSON.stringify(jsObj);
 console.log(json)

edited Jan 18, 2017 at 7:01

answered Jan 18, 2017 at 6:28

Arif H-Shigri

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Comments

Ayush Sharma · Accepted Answer · 2017-01-18 06:36:57Z

9

If you want to add new key and value to each of the key of json object and then you can use the following code else you can use the code of other answers -

Object.keys(json).map(
  function(object){
    json[object]["newKey"]='newValue'
});

answered Jan 18, 2017 at 6:36

Ayush Sharma

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Comments

Kiran Adhikari · Accepted Answer · 2019-05-25 06:48:42Z

7

 const Districts=[
  {
    "District": "Gorkha",
    "Headquarters": "Gorkha",
    "Area": "3,610",
    "Population": "271,061"
  },
  {
    "District": "Lamjung",
    "Headquarters": "Besisahar",
    "Area": "1,692",
    "Population": "167,724"
  }
]
Districts.map(i=>i.Country="Nepal")
console.log(Districts)

If you have JSON Array Object Instead of a simple JSON.

const Districts= [
  {
    "District": "Gorkha",
    "Headquarters": "Gorkha",
    "Area": "3,610",
    "Population": "271,061"
  },
  {
    "District": "Lamjung",
    "Headquarters": "Besisahar",
    "Area": "1,692",
    "Population": "167,724"
  }
]

Then you can map through it to add new keys.

Districts.map(i=>i.Country="Nepal");

answered May 25, 2019 at 6:48

Kiran Adhikari

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Comments

Shubham Khatri · Accepted Answer · 2017-01-18 05:48:40Z

3

Your object is only a JavaScript object and not JSON. You can either use brackets notation or the dot notation like

json["workbookInformation"]["new_key"] = "new_value";

var json={
    "workbookInformation": {
     "version": "9.1",
    "source-platform": "win"
    }
    
    }

json.workbookInformation.new_key = 'new_value';
console.log(json);

answered Jan 18, 2017 at 5:48

Shubham Khatri

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Comments

kkkkkkk · Accepted Answer · 2017-01-18 05:46:05Z

2

This should work:

json.workbookInformation.new_key = 'new_value';

answered Jan 18, 2017 at 5:46

kkkkkkk

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Comments

Gacci · Accepted Answer · 2017-01-18 05:46:46Z

0

json.workbookInformation.key = value;

answered Jan 18, 2017 at 5:46

Gacci

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