How to verify is set variable in object?

Question

        <script> 
        var json;
      //json = {"one":1,"two":0}
        console.log(typeof json.one); 
        console.log("How to verify is set json?"); 
        </script>

`json && typeof json === 'object' && json.hasOwnProperty('one')` — RienNeVaPlu͢s, Apr 18 '20 at 17:12
Does this answer your question? [How to check if object property exists with a variable holding the property name?](https://stackoverflow.com/questions/11040472/how-to-check-if-object-property-exists-with-a-variable-holding-the-property-name) — Christos Lytras, Apr 18 '20 at 17:21

score 2 · Accepted Answer · answered Apr 18 '20 at 17:34

if your question is if a object has certain property or not the below way works

var json = {"one":1,"two":0};
if(Object.prototype.toString.call(json) === "[object Object]" && json.hasOwnProperty('one')){
  console.log('json contains one property');
}

Proximo · Answer 2 · 2020-04-18T17:21:59.520

1

if (json && json.one) {
   console.log("It's set!");
}

edited Apr 18 '20 at 17:21

answered Apr 18 '20 at 17:15

Proximo

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What about `TypeError: json is undefined` – RienNeVaPlu͢s Apr 18 '20 at 17:19
True but the question is: How to verify is set variable in object? But let me edit my answer for you. – Proximo Apr 18 '20 at 17:21
If(typeof json.one == 'undefined") – Apr 18 '20 at 17:22

score 0 · Answer 3 · answered Apr 18 '20 at 17:22

0

If(typeof json.one == 'undefined")

answered Apr 18 '20 at 17:22

How to verify is set variable in object?

3 Answers3