If condition issue while checking for empty array

Question

I am getting output in console like {}, Now I am checking it in if condition, it does not work

$.ajax({
  ...
  success: function(data){
   if (data.length) {
        if(data.length === 0){
            $('.library_info_tbl tbody').prepend('<tr><td class="text-center centeralign" colspan="8">No Data Available!</td></tr>');
        }
        else{   
        }
    }
  });

If data contains {}, it does not check if condition i.e if(data.length === 0) does not work in the code.

Arrays [] have a length property, objects {} don't (unless you added one yourself.) — C3roe
– C3roe, Commented Nov 5, 2017 at 6:51
sucess : function(response) { console.log(response.data) } //can you tell the output — Rohit Kumar
– Rohit Kumar, Commented Nov 5, 2017 at 6:51

Akshit Grover · Accepted Answer · 2017-11-05 06:52:13Z

2

if (data.length) { ...... }

Above condition stops it from entering the inner block because 0 is treated as false, This the reason you are not able to execute your inner statement:

if(data.length === 0)

answered Nov 5, 2017 at 6:52

Akshit Grover

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Irfan TahirKheli · Accepted Answer · 2017-11-05 07:35:09Z

0

Try following:

//if data is array 
if (data.length) {     
   $('.library_info_tbl tbody').prepend('<tr><td class="text-center centeralign" colspan="8">No Data Available!</td></tr>');
}
else 
{   
}

//if data is object

if(jQuery.isEmptyObject(data)){//do something }
else{ }

edited Nov 5, 2017 at 7:35

answered Nov 5, 2017 at 6:53

Irfan TahirKheli

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5 Comments

Nida Over a year ago

if i write console,log(data); the output appears like {}

Nida Over a year ago

the above code does not work if(!data){//do something } else{ }

nnnnnn Over a year ago

if (!data) doesn't test for an empty object; even empty objects are truthy.

Irfan TahirKheli Over a year ago

you are returning array or single object from your ajax method? @Nida

Irfan TahirKheli Over a year ago

jQuery.isEmptyObject(data) this can be used to check empty object. I updated my answer. Try it @Nida

Alapan Chatterjee · Accepted Answer · 2017-11-05 08:08:49Z

0

Object in Javascript does not have a length property in their prototype.

If you are trying to find the length then first determine if it is an array or not.

success(result){
    if(result instanceof Array && result.length){ ... }
}

instanceof will determine if result is of type Array. Thus ensuring you can safely use length.

Hope it helps :-)

answered Nov 5, 2017 at 8:08

Alapan Chatterjee

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