从假定的空json响应中获取parsererror

Question

EL PROBLEMO

My JSON returns an associative array that I take elements from and display on the page. Sometimes one or more of the sub-arrays will be empty, and this is expected behavior. For those I want nothing displayed on the page. My problem is that currently anytime one of those sub-arrays is empty, I get a "parsererror". In my application, you switch between months, and this AJAX call is made when the dropdown selection is changed to a different month. On months where all the sub-arrays have values, I dont get an error. I only get it when one or more of the sub-arrays are empty.

PHP

first I perform the SQL queries, which I'm leaving out to keep this as short as possible, but these are the 3 resulting arrays:

$income = $results->fetchall(PDO::FETCH_ASSOC);
$expense = $results->fetchall(PDO::FETCH_ASSOC);
$recurring = $results->fetchall(PDO::FETCH_ASSOC);

Then I want to assign those to an array, which I then json_encode:

$array = array(
            'income'    => $income,
            'expense'   => $expense,
            'recurring' => $recurring
        );

echo json_encode($array);

AJAX

This is basically calling the previous php code, then displaying each record from the database in a table.

var request = $.ajax({
    type: "POST",
    url: 'inc/functions.php',
    dataType: "JSON",
    data: {action: "display_categories", cur_month:cur_month}
});
request.done(function(response){
    $('#income tbody tr, #expense tbody tr').remove();
        for(var i = 0; i < response.income.length; i++) {
           $('<tr><td id="' + response.income[i].cat_id_PK + '">' +         response.income[i].cat_name + '</td><td id="' + response.income[i].cat_id_PK +
'">&#36;' + response.income[i].cat_amount + '</td></tr>').appendTo("#income");
        }
        for(var i = 0; i < response.expense.length; i++) {        
           $('<tr><td id="' + response.expense[i].cat_id_PK + '">' + response.expense[i].cat_name + '</td><td id="' + response.expense[i].cat_id_PK + '">&#36;' + response.expense[i].cat_amount + '</td></tr>').appendTo("#expense");
        }
        for(var i = 0; i < response.recurring.length; i++) {
           $('<tr><td id="' + response.recurring[i].cat_id_PK + '">' +       response.recurring[i].cat_name + '</td><td id="' + response.recurring[i].cat_id_PK + '">&#36;' + response.recurring[i].cat_amount + '</td></tr>').appendTo("#expense");
        }      
});
request.fail(function(jqxhr, textStatus){
        alert("Request failed: " + textStatus);
});
};

JSON

Here's an example JSON response with two empty sub-arrays.

{
"income": [],
"expense": [],
"recurring": [
    {
        "cat_id_PK": 67,
        "cat_name": "Grooming",
        "cat_amount": "40.00",
        "recur_begin": 1,
        "recur_end": 12
    }
]
}

Answer 1

Count the number of rows you get from sql query result. if they are greater than 0 then send an extra field as

$d['status'] ='OK';

if no record exists then send the error handling as

$d['status'] ='ERR';

so check the status field in the data success

dataType: 'json',
  data: you data,
  success: function( data ) {
  if(data.status == "OK"){
    alert('success');

  } else{
    alert('failure');

  }

}
});

try like this ,just to test and then use data