Jquery code check array is null or not

Question

In the bellow code

 $.ajax({
     type: "post",
     url: "/signIn",
     dataType: "json",
     data: data,
     success: function (response) {
         alert("response----------------"+response) //[]
         if(response.length==0){
             alert("No data found")
         }
     }
  });

response is getting as [] and it doesn’t enter the if statement .

is there any possible way to check the empty array.

http://stackoverflow.com/questions/6003884/how-to-check-null-values-in-javascript — Alvaro, Sep 24 '13 at 09:26
It's not possible for `response` to be null; it has to be an array or an object - anything else would be invalid JSON and the `success` callback wouldn't execute. — Anthony Grist, Sep 24 '13 at 09:29
There in nothing wrong in `if(response.length==0)` check your console for any errors. — Deepak Ingole, Sep 24 '13 at 09:29

score 0 · Answer 1 · answered Sep 24 '13 at 09:27

$.ajax({
      type: "post",
      url: "/signIn",
      dataType: "json",
      data: data,
      success: function (response) {
        alert("response----------------"+response) //[]
        //modify if(response.length==0){
        if(!response || response.length==0){
            alert("No data found")
     }
}

Praveen · Answer 2 · 2013-09-24T10:18:54.590

I suspect that the value returned by your API is not an array, maybe an object or string.

check this using

console.log(typeof response);

Since you already use jQuery I would prefer to use jQuery.isEmptyObject()

Try like this

jQuery.isEmptyObject(response);

From your comments, Since you mentioned string, then no way other way than this

if (response === "[]") //Better
if (response.length === 2) //Not good, yet can be used

Jquery code check array is null or not

2 Answers2