JSON response data length getting undefined error in Ajax?

Question

I want to get the length of language in JavaScript alert box -

See screenshot-

Ajax Response -

enter image description here

My Ajax code -

function search_menu(){
    $.ajax({
        type: 'post',
        url: rootUrl() + "rest_apis/search_menu.json", 
        cache: false,        
        success: function(res){ //alert(data.data[0].language[142]);
            var len = res.data[0].language.length; 
            alert(len); //Showing undefined
        },
        contentType: 'application/json',
        dataType: 'json'
    });
}

I am just alerting alert(lang) its showing undefined. Actually in language having 36 record. why its showing undefined?

Your code is wrong should be: var len = res.data[0].language; ? — ssola
– ssola, Commented Feb 5, 2015 at 11:03
See my answer below : Object.keys(res.data[0].language).length — Jeremy Thille
– Jeremy Thille, Commented Feb 5, 2015 at 11:14

Jeremy Thille · Accepted Answer · 2015-02-05 11:12:15Z

8

Try : Object.keys(res.data[0].language).length

Live example :

var res = {
        "data" : [
                {
                  "language" : { "107":"english", "142":"hindi", "143" : "indonesian"}
                }
        ]
}


alert("There are " + Object.keys(res.data[0].language).length + " languages." )

edited Feb 5, 2015 at 11:12

answered Feb 5, 2015 at 11:05

Jeremy Thille

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1 Comment

eriknoyes Over a year ago

Just a bit perplexed as to why the .length property works on another page, while only your answer works on a particular one of mine. Anyway, thanks!

hari · Accepted Answer · 2015-02-05 12:03:23Z

3

Use Object.keys().forEach();.count your json length.....CHeck to click here....

var json={"data":[{"language":{"190":"english","191":"gujarati"}}]};
var length=0;
Object.keys(json.data[0].language).forEach(function(key) {
  length++; 
});
alert(length);

edited Feb 5, 2015 at 12:03

answered Feb 5, 2015 at 11:36

hari

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4 Comments

Jeremy Thille Over a year ago

What's the "use_native_lan" variable for? Why don't you just replace "forEach(function(key) { length++;});" with just ".length" ? It would be cleaner, faster, and...well, that would be my answer :)

hari Over a year ago

@JeremyThille, Sorry for that(now I changed),offcourse,it better solution,This is an another solution to find length.

Jeremy Thille Over a year ago

Sure, it works; but it's just slower, more code, more lines, more variables, more complicated. In one word it's just less elegant. So I was wondering about its interest?

hari Over a year ago

@JeremyThille,verify my code..I am using Native Javascript. Object.keys().length internally counting length(it means it use for loop). but Object.keys().forEach(function(){ //do your stuff }). you can add your own stuff inside function.so,I think both is doing same job.

Sadikhasan · Accepted Answer · 2015-02-05 11:25:06Z

2

var res={"data":[{"language":{"190":"english","191":"gujarati"}}]};
console.log( Object.keys(res['data'][0].language).length);

JS Fiddle

edited Feb 5, 2015 at 11:25

answered Feb 5, 2015 at 11:17

Sadikhasan

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3 Comments

Jeremy Thille Over a year ago

Great, that's exactly my answer :)

Sadikhasan Over a year ago

Downvoter comment will help me to improve my answer.

Jeremy Thille Over a year ago

I don't understand why people get sanctioned by downvotes so quickly, when they're just trying to help. My answer, although correct and later validated by the OP, was immediately downvoted twice. Those downvotes are just unfair.

Quentin · Accepted Answer · 2015-02-05 11:03:41Z

1

You misspelt language as languge, which is why it is undefined.

Even if you had not, it is an object not an array, so it doesn't have a length property. You'll need to count the keys to find out how many there are.

answered Feb 5, 2015 at 11:03

Quentin

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3 Comments

Quentin Over a year ago

After your edit, you should not get the result you describe. You should get [Object object] alerted.

Quentin Over a year ago

After your second edit: See the second paragraph of my answer.

Developer Over a year ago

Sorry there are typing mistake.

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