pickAnyEncoding.php

<style>
table {
border-collapse: collapse;
}
th, td {
padding: .5em 2em .5em .5em;
border-right: 1px dotted #AAA;
border-bottom: 1px solid #CCC;
}
th {
text-align: left;
border-bottom: 2px solid #000;
}
.name td:first-child + td,
.name td:first-child + td + td {
background-color: lightgreen;
}
</style>
<table>
	<thead>
		<tr>
			<th>Encoding</th>
			<th><pre><code>mb_substr($input)</code></pre></th>
			<th><pre><code>json_encode(
  mb_substr($input)
)</code></pre></th>
			<th><pre><code>mb_substr(
  mb_convert_encoding($input)
)</code></pre></th>
			<th><pre><code>json_encode(
  mb_substr(
    mb_convert_encoding($input)
  )
)</code></pre></th>
		</tr>
	</thead>
	<tbody><?php

//var_dump(mb_list_encodings());die();
$input = 'Snack 👩🏻‍🎤 with Asha';
$offsets = json_decode('[{"indices":[19,23],"id":"80541223","type":"user"}]', true);
foreach ($offsets as $offset) {
	foreach (mb_list_encodings() as $encoding) {
		$name = mb_substr($input, $offset['indices'][0], $offset['indices'][1], $encoding);
		$converted = mb_convert_encoding($input, $encoding, 'UTF-8');
		$convertedName = mb_substr($converted, $offset['indices'][0], $offset['indices'][1], $encoding);
		$row = '<tr class="' . ($name === 'Asha' ? 'name' : '') . '"><td>';
		$row .= $encoding;
		$row .= '</td><td>';
		$row .= $name;
		$row .= '</td><td>';
		$row .= json_encode($name);
		$row .= '</td><td>';
		$row .= $convertedName;
		$row .= '</td><td>';
		$row .= json_encode($convertedName);
		$row .= '</td></tr>';
		echo $row;
	}
}
?>
	</tbody>
</table>