adding new objects to array from function

Question

I already have a existing array of objects like this,

 details = [
    {
        'asjad': {
            'age': 23,
            'area': 'permiet'
        }
    }

I have a function like this,

function addValues(_arr,_name,_age){

    _arr.push({
        _name : {
            age : _age
        }
    })

}


addValues(details,'foo',24);

Where I try to add values to a array of objects by passing the values of the object to be added.

But the expected output is not foo, but instead it the key is getting added as _name

use [_name] instead of _name in the arr.push

Prasanna Brabourame
– Prasanna Brabourame

2018-10-07 07:51:47 +00:00
Commented Oct 7, 2018 at 7:51 — Prasanna Brabourame
– Prasanna Brabourame, Commented Oct 7, 2018 at 7:51

ssc-hrep3 · Accepted Answer · 2018-10-07 08:10:58Z

1

Just change the above code to this. You will achieve your need.

function addValues(_arr,_name,_age){

    _arr.push({
        [_name] : {
            age : _age
        }
    })

}

edited Oct 7, 2018 at 8:10

ssc-hrep3

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answered Oct 7, 2018 at 7:50

Prasanna Brabourame

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Comments

ssc-hrep3 · Accepted Answer · 2018-10-07 08:08:52Z

If you define an object like this in JavaScript, the key will always be a string – in your case a _name. To assign a dynamic variable as a key to an object, you'll need to use the bracket notation []. The value, however, is evaluated as an expression. In your case, _age is evaluated, because it's a value and not a key.

You could easily fix with e.g. this example:

function addValues(_arr, _name, _age){

    var object = {};
    object[_name] = {
        age: _age
    };
    _arr.push(object);

}

These are many ways to declare an object in JavaScript:

Inline Declaration:

var object = {
   _name: '123'
};

→ _name will always be a constant string.

Dot notation:

var object = {};
var object._name = '123';

→ In the dot notation, _name will also always be a constant string.

Bracket Notation:

var object = {};
var object[_name] = '123';

→ In the bracket notation, _name is an evaluated expression. In this case, a variable name _name. You could also pass a string by using object['_name'].

Computed property names:

As the other answers have pointed out, with ES6 (a newer version of JavaScript, which is not fully supported by all browsers, but can be transpiled to ES5), you could also use computed property names:

var object = {
   [_name]: '123'
};

→ In this notation, the _name will be evaluated and its value will be the key in this object. Keep in mind, that you won't have IE support without transpiling this snippet.

Imbar M. · Accepted Answer · 2018-10-07 07:48:30Z

0

function addValues(_arr,_name,_age){

    var newItem = {};
    newItem[_name] = {};
    newItem[_name]['age'] = _age;

    _arr.push(newItem);
}

answered Oct 7, 2018 at 7:48

Imbar M.

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1 Comment

Gufran Hasan Over a year ago

write some text to explain your answer.

tom10271 · Accepted Answer · 2018-10-07 07:50:01Z

0

function addValues(_arr,_name,_age){

    _arr.push({
        [_name] : {
            age : _age
        }
    })

}


addValues(details,'foo',24);

answered Oct 7, 2018 at 7:50

tom10271

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1 Comment

hcoat Over a year ago

Please take the time to explain your answer for the OP and those how may come across it in the future.

Mayur Kambariya · Accepted Answer · 2018-10-07 08:01:37Z

0

_arr.push({ [_name] : { age : _age } })

Create key value pair json you need to start key with [] for key interpolation

answered Oct 7, 2018 at 8:01

Mayur Kambariya

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