How to find the value of a dynamic key in javascript object

Question

I have a javascript object

var obj = {a:{b:'value'}};

where key 'a' is dynamic, key 'b' is constant, so I am not able to get value from obj['a'].

Is there any way to get the value of key 'b' without knowing key 'a'.

If the key is always the first (and, perhaps, the only one) in the object, you can do: obj[Object.keys(obj)[0]].b; See developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… . Alternatively, you can search for the b key: obj[Object.keys(obj).find(i => obj[i].b !== null && obj[i].b !== undefined)].b. Beware that in this second method you should also check the the find result is not null or undefined, otherwise you will have a nullreference error. — briosheje
– briosheje, Commented Sep 21, 2018 at 5:24
Possible duplicate of Get the value of an object with an unknown single key in JS — n1stre
– n1stre, Commented Sep 21, 2018 at 6:24

Aagam Jain · Accepted Answer · 2018-09-21 05:24:42Z

4

You can find all the keys of object using Object.keys(<obj>)

In your case:

key = Object.keys(obj)[0]; // will return "a"

answered Sep 21, 2018 at 5:24

Aagam Jain

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Avinash · Accepted Answer · 2018-09-21 05:25:53Z

1

Use this:

var obj = {a:{b:'value'}};
obj[Object.keys(obj)[0]].b

answered Sep 21, 2018 at 5:25

Avinash

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n1stre · Accepted Answer · 2018-09-21 05:31:27Z

1

You could use Object.values, like so:

const obj = { a: { b:'value' } };
Object.values(obj)[0].b // 'value'

answered Sep 21, 2018 at 5:31

n1stre

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Sabash · Accepted Answer · 2018-10-05 13:08:11Z

1

Try this,

res = { data: { list: { names: { blk: { cnt: 10 } } } }, test:'test' };
let val = getObjectVal(res, 'cnt')

getObjectVal(data, findKey){
let result = '';
for (let key in data) {
  if (key == findKey)
    result = data[findKey];
  if ((typeof data[key] === "object") && (data[key] !== null)) {
    if (key != findKey)
      result = getObjectVal(data[key], findKey)
  }
}
return result ? result : '';}

answered Oct 5, 2018 at 13:08

Sabash

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Raj Nandan Sharma · Accepted Answer · 2018-09-21 05:28:14Z

0

To get the value of b

var obj = {a:{b:'value'}};
console.log(obj[Object.keys(obj)[0]].b)

answered Sep 21, 2018 at 5:28

Raj Nandan Sharma

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Ramesh Kithsiri HettiArachchi · Accepted Answer · 2018-09-21 05:31:02Z

0

var obj = {a:{b:'value'}};
// Looking for each object variables in obj
Object.keys(obj).forEach(function(key){
  // Looking for each object variables in the obj[key]
 Object.keys(obj[key]).forEach(function(key2){
 // do what you want if key_2 is b
  if(key2=='b')
    console.log(obj[key][key2])
 })
})

answered Sep 21, 2018 at 5:31

Ramesh Kithsiri HettiArachchi

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