Delete row from Object

Question

I have an object containing an array:

<script type="text/javascript">
    var statusData = {
        Status: []
    };

    var uniqueCounter = 1

    function createJsonFmtData() {      

        // Used as unique id at client side 
        var uniqueCounter =uniqueCounter + 1;

        statusData.Status.push({
            "Name": Name,
            "Time": Time,
            "Email": Mail,
            "Name": Type,
            "Value": Value,
            "uniqueId": uniqueCounter
        });
    }

    function DelNewlyCreStatusRow(rowId) {
        // First pop elment from json data
        var val;
        for (val = 0; val < statusData.Status.length; ++val) {
            if (statusData.Status[val].uniqueId == rowId) {
                delete statusData.Status[val];
                break;
            }
        }
</script>

When try to call DelNewlyCreStatusRow it gives the error:

TypeError: statusData.Status[val] is undefined

I am not able to figure it out here where as I have declared it as global.

It shouldn't be undefined. Here's a fiddle, corrected a few little errors (can't remember which), seems to be working as expected: jsfiddle.net/SJB6c/1 - and yes, you're making a whole in the array, not removing and pulling the other elements back - as it'd happen with splice. You mentioned nothing about that, so I left it. — Paulo R.
– Paulo R., Commented Nov 27, 2012 at 13:14

freakish · Accepted Answer · 2012-11-27 13:00:03Z

This is because you are trying to delete from the array incorrectly. delete operator is quite funny on arrays. It replaces element with undefined. Check this out:

>>> var A = [1, 2, 3];
>>> delete a[1];
>>> A;
[1, undefined, 3];

Thus calling DelNewlyCreStatusRow multiple times will throw an exception, because statusData.Status[val].uniqueId cannot be evaluated ( statusData.Status[val] is undefined ).

To fix this use this code instead of delete:

var val;
for (val = 0; val < statusData.Status.length; ++val) {
    if (statusData.Status[val].uniqueId == rowId) {
        statusData.Status.splice( val, 1 );
        break;
    }
}

Note that splice modifies an array, so if you want to do multiple deletes in one go, then you will have to replace for loop with while ( and refactor the code a bit ). This is not needed here because of break statement.

Haocheng · Accepted Answer · 2012-11-27 12:59:56Z

1

You should replace

delete statusData.Status[val];

with

statusData.Status.splice(val,1);
val -= 1;

to remove an object in an array.

answered Nov 27, 2012 at 12:59

Haocheng

1,3431 gold badge9 silver badges15 bronze badges

Comments

phemt.latd · Accepted Answer · 2012-11-27 13:04:53Z

0

The function DelNewlyCreStatusRow missing a closing '}'

function DelNewlyCreStatusRow(rowId) {
    // First pop elment from json data
    var val;
    for (val = 0; val < statusData.Status.length; ++val) {
        if (statusData.Status[val].uniqueId == rowId) {
            delete statusData.Status[val];
            break;
        }
    }
}

answered Nov 27, 2012 at 13:04

phemt.latd

1,80323 silver badges34 bronze badges

Comments

Bernie · Accepted Answer · 2012-11-27 13:12:33Z

You made an Error in your Code at the second var declaration inside the Function. var uniqueCounter = uniqueCounter + 1 => NAN + 1. You dont need the var a Second time so it's just uniqueCounter = uniqueCounter + 1 => 2.

Then delete works fine in my Case.

<script type="text/javascript">

        var statusData = {
            Status : []
        };

        var uniqueCounter = 1

        function createJsonFmtData() {

            var statusName = $('#<%= ddlStatus.ClientID %> option:selected').text();
            var dateTime = $("#body_ctl04_ctl02").val();
            var forceMail = ($("#chkForceMail").is(':checked')) ? 1 : 0;
            var noteType = $('#divTrackId').text();
            var dataValue = $("#<%=txtTrackId.ClientID %>").val();
            var curLogedUserName = $("#<%=curLoginUserName.ClientID %>").val();

            // Used as unique id at client side
            uniqueCounter = uniqueCounter + 1;

            statusData.Status.push({

                "statusName" : statusName,
                "dateTime" : dateTime,
                "forceEmail" : forceMail,
                "typeName" : noteType,
                "dataValue" : dataValue,
                "uniqueId" : uniqueCounter
            });
        }

        function DelNewlyCreStatusRow(rowId) {

            // First pop elment from json data
            var val;
            for ( val = 0; val < statusData.Status.length; ++val) {
                if (statusData.Status[val].uniqueId == rowId) {
                    console.log(typeof(statusData.Status[val]));
                    delete statusData.Status[val];
                    break;
                }
            }
        }
        createJsonFmtData();
        console.log(statusData);
        DelNewlyCreStatusRow(2);
        console.log(statusData);
    </script>

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