hasOwnProperty does not work

Question

I got a JSON object ({error:true}) from the server.

I try to check if the object contains the key "error" and either the key exists, the function hasOwnProperty returns false.

This is my code:

$http({
        headers: { 'Content-Type': 'application/x-www-form-urlencoded;charset=utf-8;' },
        url: '/Modules/Partners/Mailing/SendMail.ashx',
        data: $.param({ contact: JSON.stringify(contact), body: partnerObject.mailTemplate.longValue, title: "" }),
        method: 'POST'
    })
    .success(function (data, status, headers, config) {
        console.log(data);
        console.log(data.hasOwnProperty('error'));

       if (data.hasOwnProperty('error')) {
           deferred.reject(contact);
       } else {
           deferred.resolve(contact);
       }
       //console.log(data)

    })
    .error(function (data, status, headers, config) {
        deferred.reject(contact);
    });

In the console I can see that the object contains the "error" key by the hasOwnProperty('error') returns false

score 6 · Answer 1 · answered Jan 03 '16 at 10:43

6

I think that the problem is with the JSON object you receive. In fact the key is not error but 'error'. Try to see if data.hasOwnProperty("'error'") works.

answered Jan 03 '16 at 10:43

mic4ael

7,974
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1

just a note that with JSON Object's you must surround the key in quotation marks not single quotes " " as opposed too ' ' Otherwise its not valid!! – Dizzy Bryan High Dec 06 '19 at 09:28

Valijon · Answer 2 · 2016-01-03T11:05:37.203

1

Your success method receives String data, not JSON:

.success(function (data, status, headers, config) {
    var result = angular.fromJson(data);

    if (result.hasOwnProperty('error')) {
        deferred.reject(contact);
    } else {
        deferred.resolve(contact);
    }
    //console.log(data)
})

BTW: If it were JSON, in console, you would see:

edited Jan 03 '16 at 11:05

answered Jan 03 '16 at 11:00

Valijon

12,667
4
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score 1 · Answer 3 · answered Feb 12 '20 at 13:33

1

You can use in operator to check if property exist on object/array. It can be used like this "error" in data // will return true

answered Feb 12 '20 at 13:33

Aditya

395
2
6

Not quite; that will tell you if the object is iterable, according to https://stackoverflow.com/a/136411/8949477. – jtunhag Nov 10 '22 at 06:52

score 0 · Answer 4 · answered Jan 03 '16 at 10:42

0

have you tried using if(data && data.error) instead of if (data.hasOwnProperty('error'))

It's probably because the error property is inherited. See more about hasOwnProperty and inherited properties here

answered Jan 03 '16 at 10:42

cguest

71
5

score 0 · Answer 5 · answered Jan 03 '16 at 10:47

check the content-type of data sent from server. it should be 'application/json' then it gets converted to javascript object implicitly. to check use "typeof data" it must be "object" else if its string then you need to parse it to object by using JSON.parse

score 0 · Answer 6 · answered Jan 03 '16 at 20:44

0

I don't know why but return the object like JsonSerializer.Serialize("{\"error\":true}");

Instead of JsonSerializer.Serialize("{'error':true}"); or JsonSerializer.Serialize("{error:true}");

Resolve my problem

answered Jan 03 '16 at 20:44

24sharon

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hasOwnProperty does not work

6 Answers6