เจอว่า json_encode มันไม่ return ผลลัพธ์ ออกมาเลยในหน้าเดียวกัน แต่ต่างกันที่ product id ลอง print_r / var_dump ตัว array ที่เข้าไปใน function ก็ปกติดี ไม่ได้มากมาย หรือมีเครื่องหมายพิเศษอะไร ลอง debug ดูถึงเจอว่าถ้าใช้ function json_last_error() มันจะ return เลข 7 กลับมาในหน้าที่มีปัญหา ลองค้นดูรหัส 7 คือ infinity number ลอง unset ตัว key ที่เป็น float(-INF) ดูก็กลับเป็นปกติจริงๆ

รหัสต่างๆ คือ

JSON error codes
Code Constant Meaning Availability
0 JSON_ERROR_NONE No error has occurred  
1 JSON_ERROR_DEPTH The maximum stack depth has been exceeded  
2 JSON_ERROR_STATE_MISMATCH Invalid or malformed JSON  
3 JSON_ERROR_CTRL_CHAR Control character error, possibly incorrectly encoded  
4 JSON_ERROR_SYNTAX Syntax error  
5 JSON_ERROR_UTF8 Malformed UTF-8 characters, possibly incorrectly encoded PHP 5.3.3
6 JSON_ERROR_RECURSION One or more recursive references in the value to be encoded PHP 5.5.0
7 JSON_ERROR_INF_OR_NAN One or moreNANor INFvalues in the value to be encoded PHP 5.5.0
8 JSON_ERROR_UNSUPPORTED_TYPE A value of a type that cannot be encoded was given PHP 5.5.0
9 JSON_ERROR_INVALID_PROPERTY_NAME A property name that cannot be encoded was given PHP 7.0.0
10 JSON_ERROR_UTF16 Malformed UTF-16 characters, possibly incorrectly encoded PHP 7.0.0

[code language=”php” title=”php_json_encode.php”]
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
<title>PHP: json_encode error</title>
<meta content="Pitt Phunsanit" name="author" />
</head>
<body>
<div class="container">
<?php
$datas = [
‘ininfity’ => -9e1000,
‘title’ => ‘title’,
];
?>
<div class="row"><label class="col-md-2" for="">Datas Arrya:</label><textarea class="col-md-10" cols="100" rows="6"><?=var_dump($datas); ?></textarea></div>
<div class="row"><label class="col-md-2" for="">Json Datas:</label><textarea class="col-md-10" cols="100" rows="6"><?=json_encode($datas); ?></textarea></div>
<div class="row">
<label class="col-md-2" for="">Json Error:</label>
<div class="col-md-10"><?=json_last_error(); ?></div>
</div>
<table class="table table-striped">
<caption><strong>JSON error codes</strong></caption>
<thead>
<tr>
<th>Code</th>
<th>Constant</th>
<th>Meaning</th>
<th>Availability</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td><strong><code><?=JSON_ERROR_NONE; ?></code></strong></td>
<td><strong><code>JSON_ERROR_NONE</code></strong></td>
<td>No error has occurred</td>
<td class="empty">&nbsp;</td>
</tr>
<tr>
<td><strong><code><?=JSON_ERROR_DEPTH; ?></code></strong></td>
<td><strong><code>JSON_ERROR_DEPTH</code></strong></td>
<td>The maximum stack depth has been exceeded</td>
<td class="empty">&nbsp;</td>
</tr>
<tr>
<td><strong><code><?=JSON_ERROR_STATE_MISMATCH; ?></code></strong></td>
<td><strong><code>JSON_ERROR_STATE_MISMATCH</code></strong></td>
<td>Invalid or malformed JSON</td>
<td class="empty">&nbsp;</td>
</tr>
<tr>
<td><strong><code><?=JSON_ERROR_CTRL_CHAR; ?></code></strong></td>
<td><strong><code>JSON_ERROR_CTRL_CHAR</code></strong></td>
<td>Control character error, possibly incorrectly encoded</td>
<td class="empty">&nbsp;</td>
</tr>
<tr>
<td><strong><code><?=JSON_ERROR_SYNTAX; ?></code></strong></td>
<td><strong><code>JSON_ERROR_SYNTAX</code></strong></td>
<td>Syntax error</td>
<td class="empty">&nbsp;</td>
</tr>
<tr>
<td><strong><code><?=JSON_ERROR_UTF8; ?></code></strong></td>
<td><strong><code>JSON_ERROR_UTF8</code></strong></td>
<td>Malformed UTF-8 characters, possibly incorrectly encoded</td>
<td>PHP 5.3.3</td>
</tr>
<tr>
<td><strong><code><?=JSON_ERROR_RECURSION; ?></code></strong></td>
<td><strong><code>JSON_ERROR_RECURSION</code></strong></td>
<td>One or more recursive references in the value to be encoded</td>
<td>PHP 5.5.0</td>
</tr>
<tr>
<td><strong><code><?=JSON_ERROR_INF_OR_NAN; ?></code></strong></td>
<td><strong><code>JSON_ERROR_INF_OR_NAN</code></strong></td>
<td>
One or more
<a class="link" href="http://php.net/manual/de/language.types.float.php#language.types.float.nan" target="_blank"><strong><code>NAN</code></strong></a>
or <a class="link" href="http://php.net/manual/de/function.is-infinite.php" target="_blank"><strong><code>INF</code></strong></a>
values in the value to be encoded
</td>
<td>PHP 5.5.0</td>
</tr>
<tr>
<td><strong><code><?=JSON_ERROR_UNSUPPORTED_TYPE; ?></code></strong></td>
<td><strong><code>JSON_ERROR_UNSUPPORTED_TYPE</code></strong></td>
<td>A value of a type that cannot be encoded was given</td>
<td>PHP 5.5.0</td>
</tr>
<tr>
<td><strong><code><?=JSON_ERROR_INVALID_PROPERTY_NAME; ?></code></strong></td>
<td><strong><code>JSON_ERROR_INVALID_PROPERTY_NAME</code></strong></td>
<td>A property name that cannot be encoded was given</td>
<td>PHP 7.0.0</td>
</tr>
<tr>
<td><strong><code><?=JSON_ERROR_UTF16; ?></code></strong></td>
<td><strong><code>JSON_ERROR_UTF16</code></strong></td>
<td>Malformed UTF-16 characters, possibly incorrectly encoded</td>
<td>PHP 7.0.0</td>
</tr>
</tbody>
</table>
</div>
</body>
</html>[/code]