Question

Quick question:

I’m using jquery ajax to call a page that returns some json data. Sometimes it returns full of data and sometimes it returns empty as [].

I want the script to do different things if it comes back empty[] or with data. Everything is working fine when it returns with data, but I can’t seem to get things to work when it returns empty as []. Here’s what i have:

success: function (returndata){
      if (returndata === null)
      {
          $("#versionBox").remove();
      }
 else {
        $.each(returndata, function()
               {
                   var tag = this["name"];
                   var linkname = "textdisplay.php?flag=<?php echo $fs; ?>&ed=" + tag;
                       $('#versionBox').append("<p><a href='" + linkname + "'>" +  tag + "</a></p>");
               });

      }

But null doesn’t seem to be the correct way to describe [] because the first part of this script isn’t working.

Thanks for your advice.

Answer 1

First, check if it’s an array Check if object is array?, then if its returndata.length == 0. Done & done!

if( Object.prototype.toString.call( returnData ) === '[object Array]' ) {
    if(returnData.length == 0)
        alert( 'it is []' );
}

The “is it an array” check isn’t very satisfying, I know…