Delete null values in nested javascript objects

Question

I have a nested object and want to remove all key/value pairs if the value is null or undefined. I've managed to get the below code working but it doesn't check the nested key/value pairs and wondered if someone could help me figure out what needs adding to the code please?

var myObj = {
  fName:'john',
  lName:'doe',
  dob:{
    displayValue: null, 
    value: null
  },
  bbb:null
};

function clean(obj) {
  for (var propName in obj) { 
    if (obj[propName] === null || obj[propName] === undefined || obj[propName] === '') {
      delete obj[propName];
    }
  }
  return obj;
}
console.log(clean(myObj));

The above code does the job to remove 'bbb' and its value and I want the same done for the nested object represented by 'dob' as well.

https://jsbin.com/mudirateso/edit?js,console,output

Any help is greatly appreciated.

you need to write a recursive function that calls clean() on any sub-objects. — Barmar
– Barmar, Commented Nov 14, 2017 at 22:37
StackOverflow expects you to try to solve your own problem first, and we also don't answer homework questions. Please update your question to show what you have already tried in a minimal, complete, and verifiable example. For further information, please see how to ask good questions, and take the tour of the site :) — Barmar
– Barmar, Commented Nov 14, 2017 at 22:38

CRice · Accepted Answer · 2017-11-14 22:39:22Z

1

You're already almost there. Just have the function recurse if the property is another object:

var myObj = {
  fName:'john',
  lName:'doe',
  dob:{
    displayValue: null, 
    value: null
  },
  bbb:null
};

function clean(obj) {
  for (var propName in obj) { 
    if (obj[propName] === null || obj[propName] === undefined || obj[propName] === '') {
      delete obj[propName];
    } else if (typeof obj[propName] === "object") {
      // Recurse here if the property is another object.
      clean(obj[propName])
    }
  }
  return obj;
}
console.log(clean(myObj));

answered Nov 14, 2017 at 22:39

CRice

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2 Comments

SLaks Over a year ago

But beware of infinite recursion.

Jayonline Over a year ago

Thank you both!! Much appreciated. @CRice

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