How to assign values to an array of object with same key names

Question

 let personNames = [ { firstName: 'Ben' }, {firstName : 'Bob' } ];
 let details=  { city: 'Dublin' , Country: 'Ireland' } ;
 let nameList = [];
 let nameObj = {};
 for(let name of personNames){
   nameObj = details;
   nameObj['f_name'] = name.firstName;
   nameList.push(nameObj);
 }

expected output :

[ {fname:'Ben', city: 'Dublin' , Country: 'Ireland'}, {fname:'Bob',city: 
'Dublin' , Country: 'Ireland'}]

what I'm getting is:

[ {fname:'Ben', city: 'Dublin' , Country: 'Ireland'}, {fname:'Ben', city: 'Dublin' , Country: 'Ireland'}}]

What am I doing wrong here?

you are using the same nameObj reference.. declare inside your for loop — Suraj Rao
– Suraj Rao, Commented Feb 13, 2018 at 10:43
let nameList = personNames.map(person => ({ fName: person.firstName })) — dfsq
– dfsq, Commented Feb 13, 2018 at 10:46

Stefan Matcovici · Accepted Answer · 2018-02-13 10:45:55Z

3

What are you doing here is pushing into the array the same reference. You could create each time the nameObj into the for loop in order to have references to different objects in your array.

 let personNames = [ { firstName: 'Ben' }, {firstName : 'Bob' } ];
 let nameList = [];
 for(let name of personNames){
   let nameObj = {};
   nameObj['f_name'] = name.firstName;
   nameList.push(nameObj);
 }

answered Feb 13, 2018 at 10:45

Stefan Matcovici

1063 bronze badges

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

Comments

Orelsanpls · Accepted Answer · 2018-02-13 10:54:34Z

1

You can achieve it using Array.map method, which is ES6

const personNames = [{
  firstName: 'Ben',
}, {
  firstName : 'Bob',
}];

const nameList = personNames.map(x => ({
  f_name: x.firstName,
}));
 
 
console.log(nameList);

We are looping through personNames, and for each element in it, we are creating a new object which contains a key named f_name.

answered Feb 13, 2018 at 10:54

Orelsanpls

23.7k7 gold badges46 silver badges74 bronze badges

Comments

Abdullah Aftab · Accepted Answer · 2018-02-13 10:43:08Z

0

nameObj should be inside the for loop

answered Feb 13, 2018 at 10:43

Abdullah Aftab

501 silver badge4 bronze badges

Collectives™ on Stack Overflow

How to assign values to an array of object with same key names

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