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I have a javascript object with multiple nested objects like this :

 var stats = {
     bookServed: {
         redis: 90,
         s3: 90,
         signedUrl: 70
     },
     errors: {
         redis: {
             bookService: 70,
             mapi: 50,
             capi: 30
         },
         AWS: {
             signedUrl: 70,
             downloadBook: 50,
             searchBook: 10
         },
         decryption: 60
     }
 };

What would be the cleanest way to iterate through all its properties and set each value to 0 for instance. I wrote something like this

 for (var property in stats) {
     if (stats.hasOwnProperty(property)) {
         if (typeof property === "object") {
             for (var sub_property in property)
                 if (property.hasOwnProperty(sub_property)) {
                     sub_property = 0
                 }
         } else {
             property = 0;
         }
     }
 }

I'm willing to use a library like underscore.js to do the task properly.

I have a javascript object with multiple nested objects like this :

 var stats = {
     bookServed: {
         redis: 90,
         s3: 90,
         signedUrl: 70
     },
     errors: {
         redis: {
             bookService: 70,
             mapi: 50,
             capi: 30
         },
         AWS: {
             signedUrl: 70,
             downloadBook: 50,
             searchBook: 10
         },
         decryption: 60
     }
 };

What would be the cleanest way to iterate through all its properties and set each value to 0 for instance. I wrote something like this

 for (var property in stats) {
     if (stats.hasOwnProperty(property)) {
         if (typeof property === "object") {
             for (var sub_property in property)
                 if (property.hasOwnProperty(sub_property)) {
                     sub_property = 0
                 }
         } else {
             property = 0;
         }
     }
 }

I'm willing to use a library like underscore.js to do the task properly.

• javascript
• node.js
• object
• underscore.js

Share Improve this question Follow edited Oct 13, 2015 at 21:04 Kevin B 95.1k1616 gold badges167167 silver badges186186 bronze badges asked Oct 13, 2015 at 20:54 AmaynutAmaynut 4,27177 gold badges4444 silver badges4646 bronze badges 5

• Any library you use is going to use a similar method of recursive looping. I assume what you have works, and you're just looking for something... "cleaner" (whatever that means)? – Kevin B Commented Oct 13, 2015 at 20:58
• My solution works only for 2 levels of nested objects, in my example I have 3 level, that's why I want something recursive that go to the deepest level no matter how many levels I have in my object. – Amaynut Commented Oct 13, 2015 at 21:01
• so make a function that does the step, and if an object is found instead of a number, call the function again on the sub object. – Kevin B Commented Oct 13, 2015 at 21:02
• Ok I got the idea, but how to make it recursive? – Amaynut Commented Oct 13, 2015 at 21:05
• 2 "and if an object is found instead of a number, call the function again on the sub object." that would make it recursive. – Kevin B Commented Oct 13, 2015 at 21:06

Add a ment  | 

3 Answers 3

Sorted by: Reset to default 7

Relatively simple recursion problem, I would use a function that calls itself when sub objects are found. I would also avoid using a for in loop, and instead use a forEach on the object's keys (it's much faster, and doesn't require a hasOwnProperty check.)

function resetValuesToZero (obj) {
    Object.keys(obj).forEach(function (key) {
        if (typeof obj[key] === 'object') {
            return resetValuesToZero(obj[key]);
        }
        obj[key] = 0;
    });
}

var stats = {
     bookServed: {
         redis: 90,
         s3: 90,
         signedUrl: 70
     },
     errors: {
         redis: {
             bookService: 70,
             mapi: 50,
             capi: 30
         },
         AWS: {
             signedUrl: 70,
             downloadBook: 50,
             searchBook: 10
         },
         decryption: 60
     }
 };

console.log(stats.errors.AWS.signedUrl); // 70
resetValuesToZero(stats);
console.log(stats.errors.AWS.signedUrl); // 0

The below solution uses object-scan, which uses an iterative implementation to traverse the input. Also note that this will traverse into any array structures similar to the accepted answer.

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

const rewriter = objectScan(['**'], {
  rtn: 'count',
  filterFn: ({ value, parent, property }) => {
    if (typeof value === 'number') {
      parent[property] = 0;
      return true;
    }
    return false;
  }
});

const stats = { bookServed: { redis: 90, s3: 90, signedUrl: 70 }, errors: { redis: { bookService: 70, mapi: 50, capi: 30 }, AWS: { signedUrl: 70, downloadBook: 50, searchBook: 10 }, decryption: 60 } };

console.log(rewriter(stats)); // returns count of replaces
// => 10

console.log(stats);
/* =>
{ bookServed: { redis: 0, s3: 0, signedUrl: 0 },
  errors:
  { redis: { bookService: 0, mapi: 0, capi: 0 },
    AWS: { signedUrl: 0, downloadBook: 0, searchBook: 0 },
    decryption: 0 } }
*/

.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

function checkNPE(obj) {
  for(const name in obj){console.log('name: ' + JSON.stringify(name, null, 4));
    if (typeof obj[name] === 'object') {console.log('object name: ' + JSON.stringify(name, null, 4));
      checkNPE(obj[name]);
    } // if (typeof obj[name] === 'object') {
  } // for(const name in obj){
}; // function checkNPE (obj) {

var stats = {
     bookServed: {
         redis: 90,
         s3: 90,
         signedUrl: 70
     },
     errors: {
         redis: {
             bookService: 70,
             mapi: 50,
             capi: 30
         },
         AWS: {
             signedUrl: 70,
             downloadBook: 'a',
             searchBook: 10
         },
         decryption: 60
     }
 };
checkNPE(stats);

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