PHP and JSON - extra comma in results - php

Question

I'm trying to return json response in the correct format but I am getting an extra 'comma' in the returned code (comma after the last item 'Pencil'):
{
"results": [{
"ItemID": 1,
"ItemName": "Ball"
}, {
"ItemID": 2,
"ItemName": "Pen"
}, {
"ItemID": 3,
"ItemName": "Pencil"
},
}]
}
I tried different things but I can't get rid of it. Would anybody have any idea how to remove it?
The code that i have is this:
<?php
print '{"results":[';
for ($i=0; $i <$numrows; $i++) {
$stmt->fetch();
$JSONArray = array(
"ItemID" => $ItemID,
"ItemName" => $ItemName
);
print ",";
print json_encode($JSONArray);
}
print "]}"
?>

Answer 1

You're doing it ENTIRELY wrong. You're outputting multiple independent JSON strings, which is outright wrong. JSON is a monolithic "structure", and building it piece-wise is highly risky.
Simple: DOn't do that.
You build a standard PHP array, then do ONE SINGLE encoding when you're completely done building:
$arr = array();
for(...) {
$arr[] = ... add stuff ..
}
echo json_encode($arr);

Answer 2

First, fetching into bound variables is causing you an extra step, second, you don't need to construct any JSON. Just get all of your rows into the proper array structure and encode:
$result = $stmt->get_result();
while($rows['results'][] = $result->fetch_array(MYSQLI_ASSOC)){}
echo json_encode($rows);
If your system supports it, just use this instead of the while loop:
$rows['results'] = $result->fetch_all(MYSQLI_ASSOC);