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 -

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?

Solution 1

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." )

Solution 2

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);

Solution 3

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

JS Fiddle

Solution 4

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.

View more solutions

Comments

[Quentin]

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

[Developer]

Great answer. Thanks :)

[Quentin]

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

[Jeremy Thille]

Great, that's exactly my answer :)

[Developer]

Sorry there are typing mistake.

[Sadikhasan]

Downvoter comment will help me to improve my answer.

[Jeremy Thille]

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.

[Jeremy Thille]

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]

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

[Jeremy Thille]

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]

@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.

[eriknoyes]

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!