CODEWITHSUNDEEP
javascriptobject
Luuk Gortzak
Luuk Gortzak

Reputation: 165

Replace object value with other object's value of the same key with JavaScript

I've got two objects, item and results. They've both got the same keys but possibly different values, for example:

item.id = '50'
item.area = 'Mexico'
item.gender = null
item.birthdate = null

results.id = '50'
results.area = null
results.gender = 'Male' 
results.birthdate = null

What I want to do is exactly the following:

if (item.id == null || items.id == 0)
{
    item.id = results.id;
}

but I'm looking for a way to do this for each value of my item object. You know, without having to write a huge function if my objects happen to have a lot more keys / values. Any ideas?

Update : I misunderstood my own problem and the only issue was that I didnt really understand how to get an object value given a certain key. I couldnt really use any outside scripts or divs since Im using Azure's mobile service scripts.

for (var key in item) {
    if(item[key] == null || item[key] == 0){
        item[key] = results[0][key] 
    }             
}

Upvotes: 15

Views: 86473

Answers (7)

Sean
Sean

Reputation: 721

You can also use the nullish coalescing operator and a reduce function to simplify it a bit.

var item = {
  id: '50',
  area: 'Mexico',
  gender: null,
  birthdate: null
};
var results={
  id: '50',
  area: null,
  gender: 'Male',
  birthdate: null
};

item = Object.keys(item).reduce((acc, key) => {
  acc[key] = acc[key] ?? results[key];
  return acc;
}, item);

document.getElementById('dbg').innerHTML ='<pre>' + JSON.stringify(item , null , ' ') + '</pre>';

console.dir(item);
<div id='dbg'></div>

Upvotes: 2

Cappa
Cappa

Reputation: 117

For the one liner, here is an option:

{ ...item, ...Object.keys(results).reduce((pv, cv) => results[cv] == null ? pv : { ...pv, [cv]: results[cv] }, {}) };

Upvotes: 1

l_r
l_r

Reputation: 1060

Old post but if you search a more recent straightforward solution you can try Object.assign(). Properties in the target object are overwritten by properties in the sources if they have the same key.

const target = { a: 1, b: 2 };
const source = { b: 4, c: 5 };

const returnedTarget = Object.assign(target, source);

console.log(target);
// expected output: Object { a: 1, b: 4, c: 5 }

console.log(returnedTarget);
// expected output: Object { a: 1, b: 4, c: 5 }

Upvotes: 2

Dory Zidon
Dory Zidon

Reputation: 10719

You could just iterate all the object keys, and then write assign them on each item:

for (var property in results) {
    if (results.hasOwnProperty(property) && !item[property]) {
        // do stuff
        item[property] = results[property]
    }
}

Upvotes: 0

Anonymous0day
Anonymous0day

Reputation: 3042

It could do the trick !

var item = {};
var results={};

item.id = '50'
item.area = 'Mexico'
item.gender = null
item.birthdate = null

results.id = '50'
results.area = null
results.gender = 'Male'
results.birthdate = null

Object.keys(item).forEach(function(key) {
  if (item[key] == null || item[key] == 0) {
    item[key] = results[key];
  }
})
document.getElementById('dbg').innerHTML ='<pre>' + JSON.stringify(item , null , ' ') + '</pre>';

console.dir(item);
<div id='dbg'></div>

Upvotes: 15

Meir
Meir

Reputation: 14395

You can elegantly use lodash:

var results = {};
var item = {};

item.id = '50';
item.area = 'Mexico';
item.gender = null;
item.birthdate = null;

results.id = '50';
results.area = null;
results.gender = 'Male'; 
results.birthdate = null;

_.merge(results, _.pick(item, _.identity));

alert(JSON.stringify(results));
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/3.10.1/lodash.js"></script>

Note that the requested value is now in results (and not in item). If you still need it item, clone the values into a new variable and use it.

Upvotes: 4

AtheistP3ace
AtheistP3ace

Reputation: 9691

You can loop over the object like this. hasOwnProperty tests if it is a property defined by you and not from the base object definition.

for (var key in item) {
   if (item.hasOwnProperty(key)) {
       if (item[key] == null) {
           item[key] = results[key];
       }
   }
}

Upvotes: 2

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