How to recursively set empty objects {} to null?

Question

I have a few empty objects in my JSON request:

FXP:

"createdBy": {},

I would like to before the request is sent to the server convert these empty objects into following structure:

"createdBy": null,

How can I do it recursively in whole object please?

Example:

{
    "main": {
        "id": null,
        "archived": true,
        "createdBy": {},
        "creationTime": null,
        "location": {
            "id": 79,
            "address": {
                "id": 79,
                "city": null,
                "latitude": 50.072613888888895,
                "longitude": 14.543111111111111,
                "street": null,
                "streetNumber": null,
                "district": null
            },
            "bsc": "BSC123",
            "code": null,
            "indoorOutdoor": null,
            "siteId": "A0RST",
            "stationType": {
                "id": 1,
                "name": "Indoor solution"
            },
            "shared": false,
            "sapSacIrnCode": "31049.0",
            "abloyLocation": "NA",
            "name": "A0RST"
        },
        "actionName": {},
        "orderType": {},
        "project": {
            "id": 1,
            "cards": [],
            "color": null,
            "managerCustomer": null,
            "managerSuntel": null,
            "heliosSync": false,
            "name": "Vodafone Test",
            "parentProject": null,
            "team": null,
            "facility": {
                "id": 1,
                "code": 110,
                "name": "110_MANAGEMENT"
            },
            "workers": []
        },
        "note": "",
        "orderNumber": "2626262"
    },
    "milestoneSequence": {},
    "milestones": []
}

May I ask why you want to do this? It might be easier to process server side. — Brian Glaz
– Brian Glaz, Commented Mar 20, 2015 at 14:20
Could you provide some more context? How deep is everything nested? You can use Object.keys(your_object).forEach(callback) to loop over an object and then you can check Object.keys(sub_object) to see how many keys it has. If it has no keys you can set it to null. This could get very messy I think if you want to go very deep with this check.. — donnywals
– donnywals, Commented Mar 20, 2015 at 14:20
So this really has nothing to do with JSON right? You are just wanting to replace empty objects in your root object with null before even serializing to JSON correct? — Mike Brant
– Mike Brant, Commented Mar 20, 2015 at 14:28

Pavel Gatnar · Accepted Answer · 2015-03-20 14:30:46Z

4

In JSON.parse resp. JSON.stringify you can pass a function as the 2nd argument.
This function gets name and value as arguments.
So you can adjust the values during parsing resp. stringifying.

edited Mar 20, 2015 at 14:30

answered Mar 20, 2015 at 14:21

Pavel Gatnar

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7 Comments

thefourtheye Over a year ago

You mean JSON.stringify, right?

blex Over a year ago

Yes, JSON.parse is for String->object. JSON.stringify is for object->String.

redrom Over a year ago

This is the object, not string. I won't to modify object to string, update and then convert back into object.

Lye Fish Over a year ago

The OP's phrasing is a little confusing since he starts out calling it JSON. Either way, it can be done with a callback.

Pavel Gatnar Over a year ago

thanx for your comments, as I saw JSON request, I understood it is already a string... I adjusted my answer...

|

Turbcool · Accepted Answer · 2019-07-11 13:55:21Z

1

Here is a recursive function that might help you:

function nullify  (obj) { 
   for(key in obj) { 
      if(JSON.stringify(obj[key])=="{}") {
          obj[key] = null;
      } else if (typeof obj[key] == "object" && !Date.parse(obj[key])) {
          obj[key] = nullify(obj[key]);
      }
   }
   return obj;
}

for this example :

var obj = {
  "b": 1,
  "c": {},
  "d": {
    "a": 1,
    "b": {},
    "c": {
      "x": 1,
      "y": {}
    }
  }
}

the result of nullify(obj); is

{
  "b": 1,
  "c": null,
  "d": {
    "a": 1,
    "b": null,
    "c": {
      "x": 1,
      "y": null
    }
  }
}

edited Jul 11, 2019 at 13:55

Turbcool

1148 bronze badges

answered Mar 20, 2015 at 14:27

Khalid

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4 Comments

Khalid Over a year ago

can you post the json object you used ?

Khalid Over a year ago

It worked for me, just try again, may be you tried the old version of the function, georg edited an error on it. try again and let me know if it worked

redrom Over a year ago

Still same error ReferenceError: key is not defined, could be caused by 'undefined' value in object?

Khalid Over a year ago

Are you sure you tried the json object you have posted on your question ? because I tried it and it worked, I even added an undefined value and there was no error, please post the json object you that caused this error

Thor Jacobsen · Accepted Answer · 2015-03-20 14:37:17Z

0

If you don't like using strings too much:

function emptyObjToNull(object){
    var isObject, hasKeys, isArray, current;
    for(var k in object){
        if(!object.hasOwnProperty(k))
            return;
        current = object[k];
        isObject = typeof current == 'object';
        hasKeys = isObject && Object.keys(current).length !== 0;
        isArray = isObject && Object.prototype.toString.call(current) === "[object Array]";
        if(hasKeys){
            emptyObjToNull(current);
        }else if(isArray){
            for(var i = current.length; i--;){
                emptyObjToNull(current);
            }
        }else if(isObject && !hasKeys){
            object[k] = null; // Set the key directly, not the reference
        }
    }
}

Fiddle: http://jsfiddle.net/cfvm3r63/3/

edited Mar 20, 2015 at 14:37

answered Mar 20, 2015 at 14:31

Thor Jacobsen

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1 Comment

redrom Over a year ago

I solved it using: var orderString = JSON.stringify($scope.order); var orderStringRaplaced = orderString.split("{}").join(null);

vincent · Accepted Answer · 2021-01-07 01:00:26Z

Here is a solution using object-scan. Depending on your scenario using a dependency might make sense

// const objectScan = require('object-scan');

const data = {"main":{"id":null,"archived":true,"createdBy":{},"creationTime":null,"location":{"id":79,"address":{"id":79,"city":null,"latitude":50.072613888888895,"longitude":14.543111111111111,"street":null,"streetNumber":null,"district":null},"bsc":"BSC123","code":null,"indoorOutdoor":null,"siteId":"A0RST","stationType":{"id":1,"name":"Indoor solution"},"shared":false,"sapSacIrnCode":"31049.0","abloyLocation":"NA","name":"A0RST"},"actionName":{},"orderType":{},"project":{"id":1,"cards":[],"color":null,"managerCustomer":null,"managerSuntel":null,"heliosSync":false,"name":"Vodafone Test","parentProject":null,"team":null,"facility":{"id":1,"code":110,"name":"110_MANAGEMENT"},"workers":[]},"note":"","orderNumber":"2626262"},"milestoneSequence":{},"milestones":[]};

const nullify = (input) => objectScan(['**'], {
  rtn: 'count',
  filterFn: ({ value, parent, property }) => {
    if (
      value instanceof Object
      && !Array.isArray(value)
      && Object.keys(value).length === 0
    ) {
      parent[property] = null;
      return true;
    }
    return false;
  }
})(input);

console.log(nullify(data)); // returns number of changes
// => 4
console.log(data);
// => { main: { id: null, archived: true, createdBy: null, creationTime: null, location: { id: 79, address: { id: 79, city: null, latitude: 50.072613888888895, longitude: 14.543111111111111, street: null, streetNumber: null, district: null }, bsc: 'BSC123', code: null, indoorOutdoor: null, siteId: 'A0RST', stationType: { id: 1, name: 'Indoor solution' }, shared: false, sapSacIrnCode: '31049.0', abloyLocation: 'NA', name: 'A0RST' }, actionName: null, orderType: null, project: { id: 1, cards: [], color: null, managerCustomer: null, managerSuntel: null, heliosSync: false, name: 'Vodafone Test', parentProject: null, team: null, facility: { id: 1, code: 110, name: '110_MANAGEMENT' }, workers: [] }, note: '', orderNumber: '2626262' }, milestoneSequence: null, milestones: [] }

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

<script src="https://bundle.run/[email protected]"></script>

Disclaimer: I'm the author of object-scan

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