jQuery Ajax Callback for array result

Question

I have following jQuery Ajax scenario in which a webmethod returns a collection of strings.

The collection can be null
The collection can be non-null but zero records.
The collection has one or more records

The following code works fine. It uses jQuery.isEmptyObject. It is advised not to use isEmptyObject() when it is not a Plain Object.

How can we handle the result without using isEmptyObject() ?

Note: The ajax "result" is coming as "not plain".

Reference:

CODE

//Callback Function
function displayResultForLog(result) 
{


if (result.hasOwnProperty("d")) 
{
    result = result.d
}


if ($.isPlainObject(result)) {
    alert('plain object');
}
else 
{
    alert('not plain');
}

if($.isEmptyObject(result))
{
    //Method returned null        
    $(requiredTable).append('No data found for the search criteria.');
}
else
{

    if (result.hasOwnProperty('length')) 
    {

        //Set the values in HTML
        for (i = 0; i < result.length; i++) 
        {
            var sentDate = result[i];
        }
    }

    else 
    {
      //Method returned non-null object; but there is no rows in that        
      $(requiredTable).append('No data found for the search criteria.');
    }

  }

 }

function setReportTable(receivedContext) {

var searchInput = '111';
$.ajax(
        {
            type: "POST",
            url: "ReportList.aspx/GetReportsSentWithinDates",
            data: '{"searchInput": "' + searchInput + '"}',
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            context: receivedContext, //CONTEXT
            success: displayResultForLog

        }
        );
 }

daveyfaherty · Answer 1 · 2016-10-16T17:34:52.947

0

Instead of

if($.isEmptyObject(result))

would

if(typeof result !== 'undefined' && result.length < 1)

work?

Reference for undefined is here JavaScript undefined Property

The undefined property indicates that a variable has not been assigned a value.

edited Oct 16 '16 at 17:34

answered Dec 03 '12 at 12:44

daveyfaherty

4,585
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1

Good point, I've amended by suggestion to check if the object isn't undefined. – daveyfaherty Dec 03 '12 at 12:56
1

Is it `!== "undefined"` or `!== undefined`? – LCJ Feb 12 '13 at 07:00
Good catch, in this case, 'undefined' is what we should be looking for – daveyfaherty Feb 13 '13 at 10:48

LCJ · Accepted Answer · 2013-02-12T06:59:19.330

At present I am using the following. Any improvement suggestions?

 function displayResultForLog(result) 
 {
   if (result.hasOwnProperty("d")) {
       result = result.d
   }

if (result !== undefined && result != null )
{
    if (result.hasOwnProperty('length')) 
    {
        if (result.length >= 1) 
        {
            for (i = 0; i < result.length; i++) {

                var sentDate = result[i];

            }
        }
        else 
        {
            $(requiredTable).append('Length is 0');
        }
    }

    else 
    {
        $(requiredTable).append('Length is not available.');
    }

}
else 
{
    $(requiredTable).append('Result is null.');
}
}

Reference for undefined is here JavaScript undefined Property

The undefined property indicates that a variable has not been assigned a value.

jQuery Ajax Callback for array result

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