How to update dynamically an object in Javascript?

Question

I've got an object and I want to update it with new data. But, if one of the keys has a value of undefined, I want it to have the same value it was priorly defined.

let obj 

obj = {
  name: 'Bill'
  job: 'dev'
  age: 22
}

const newObj = {
  name: 'Sam',
  age: 33
}

Object.keys(obj).forEach(key => {
  obj[key] = newObj[key];
});

I want obj to return:

{
  name: "Sam"
  job:'dev',
  age: 33,

}

But it returns:

{
  age: 33,
  job: undefined,
  name: "Sam"
}

Also, it would help to return in the same order as the original.

472 The iteration order for objects follows a certain set of rules since ES2015, but it does not (always) follow the insertion order. Simply put, the iteration order is a combination of the insertion order for strings keys, and ascending order for number-like keys. — jaibalaji
– jaibalaji, Commented May 29, 2020 at 15:01
@adiga - It could still exist and have the value undefined... — T.J. Crowder
– T.J. Crowder, Commented May 29, 2020 at 15:01

palaѕн · Accepted Answer · 2020-05-29 14:59:37Z

1

You can simply merge the objects using spread syntax like:

let obj 

obj = {
  name: 'Bill',
  job: 'dev',
  age: 22,
}

const newObj = {
  name: 'Sam',
  age: 33,
}

obj= {...obj, ...newObj}
console.log( obj )

answered May 29, 2020 at 14:59

palaѕн

74.2k17 gold badges123 silver badges140 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

YogendraR · Accepted Answer · 2020-05-29 15:00:07Z

0

you can do this:

Object.keys(obj).forEach(key => {
 obj[key] = newObj[key] ? newObj[key] : obj[key];
});

answered May 29, 2020 at 15:00

YogendraR

2,40616 silver badges19 bronze badges

Comments

Bertug · Accepted Answer · 2020-05-29 15:06:10Z

0

let obj 

obj = {
  name: 'Bill',
  job: 'dev',
  age: 22
}

const newObj = {
  name: 'Sam',
  age: 33
}

obj= {
  ...obj,
  ...newObj
}

Spread will solve your problem. newObject properties will override object properties. (same properties for override)

answered May 29, 2020 at 15:06

Bertug

1,1762 gold badges13 silver badges34 bronze badges

Collectives™ on Stack Overflow

How to update dynamically an object in Javascript?

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related