javascript - how to check if exists child object value of key in object?

Question

{
    "cd": {},
    "person": {},
    "p2": {
        "foo1": {},
        "foo2": {}
    }
}

"cd" doesn't have child object (empty object).

"p2" has child object.

how to check if exists child object value?

Do you want to check the existence of a specific property of whether it has any properties at all? — Felix Kling, Sep 27 '17 at 00:52
@FelixKling i want to check any properties at all using for loop — Yunhee, Sep 27 '17 at 00:58

score 2 · Answer 1 · answered Sep 27 '17 at 00:55

For specific child name you can try this:

var object = {
    "cd": {},
    "person": {},
    "p2": {
        "foo1": {},
        "foo2": {}
    }
}

if (object.cd.hasOwnProperty("childName")) {
// Do some stuff here
}

if you are looking for any child into the object you can try this

const objectToCheckIfHasChildren = object.cd;
const children = Object.keys(objectToCheckIfHasChildren);

if (children.length > 0) {
  // then children has at least one child
}

score 1 · Accepted Answer · answered Sep 27 '17 at 00:53

1

function hasChild(obj){
  return !!Object.keys(obj).length;
}
var obj = {
    "cd": {},
    "person": {},
    "p2": {
        "foo1": {},
        "foo2": {}
    }
};
console.log(hasChild(obj.cd));
console.log(hasChild(obj.p2));

answered Sep 27 '17 at 00:53

Isaac

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score 0 · Answer 3 · answered Sep 27 '17 at 00:56

Here's a way that'll handle null and undefined as well.

function isEmpty(obj) {
  for (const _ in obj) return false;
  return true;
}

You can add a .hasOwnProperty() check if you're worried about inherited, enumerable properties.

So an empty object, null and undefined will return true (being empty), otherwise false is returned.

javascript - how to check if exists child object value of key in object?

3 Answers3