javascript - How to recursively set empty objects {} to null? - Stack Overflow

admin管理员组

文章数量:1417070

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": []
}

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": []
}

• javascript

Share Improve this question Follow edited Apr 7, 2022 at 19:18 Braiam 4,4961111 gold badges4949 silver badges8383 bronze badges asked Mar 20, 2015 at 14:17 redromredrom 11.6k3434 gold badges166166 silver badges269269 bronze badges 3

• 1 May I ask why you want to do this? It might be easier to process server side. – 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 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 Commented Mar 20, 2015 at 14:28

Add a ment  | 

4 Answers 4

Sorted by: Reset to default 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.

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
    }
  }
}

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/cfvm3r63/3/

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

本文标签： javascriptHow to recursively set empty objectsto nullStack Overflow