How to get to item in object with Object.keys

Question

I have been starting to look at javascript objects, and I have found the format that looks like this.

var obj = {
        prop1: 5,
        obj2: {
          prop1: [3, 6, 3],
          prop2: 74,
          4_3: {
            str: "Hello World"
          }
        }
      };

My question is. How do I get the console to say the string?

I have tried something like this:

console.log(obj.obj2[Object.keys(obj.obj2)[2]].str);

But it didn't work.

*Why* are you trying to do it this way? In fact, what is the overall goal? [Does ES6 introduce a well-defined order of enumeration for object properties?](https://stackoverflow.com/q/30076219) explains why `2` is the wrong index here but I really don't see why you'd even want to use an indexed key. — VLAZ, Dec 04 '21 at 15:36
`console.log(obj.obj2['43'].str);` (which explains why you were using Object.keys to access it, but as VLAZ noted integer keys are sorted before string keys). — pilchard, Dec 04 '21 at 15:42
To clarify, the underscore is treated as a [numeric seperator](https://v8.dev/features/numeric-separators) so the property is just `43` — pilchard, Dec 04 '21 at 15:51

score 0 · Answer 1 · answered Dec 04 '21 at 15:48

0

I'm not change the input this time

var obj = {
  prop1: 5,
  obj2: {
    prop1: [3, 6, 3],
    prop2: 74,
    4_3: {
      str: "Hello World"
    }
  }
};

console.log(obj.obj2[Object.keys(obj.obj2)[0]].str);

answered Dec 04 '21 at 15:48

Fatur

141
9

1

but how would you know it was index 0. – pilchard Dec 04 '21 at 15:49
Because alphabetical order. And number come first before string. – Fatur Dec 04 '21 at 15:51
I understand that, and VLAZ already commmented to that effect, but how is this clearer than just accessing the actual key `['43']`? – pilchard Dec 04 '21 at 15:53

score 0 · Answer 2 · answered Dec 04 '21 at 17:06

0

Why not just reference?

var obj = {
        prop1: 5,
        obj2: {
          prop1: [3, 6, 3],
          prop2: 74,
          4_3: {
            str: "Hello World"
          },
        }
      };
      
console.log(obj.obj2['43'].str);

answered Dec 04 '21 at 17:06

Ran Turner

14,906
5
47
53

How to get to item in object with Object.keys

2 Answers2