--TEST-- MongoDB\BSON\UTCDateTime::jsonSerialize() with json_encode() --FILE-- <?php require_once __DIR__ . '/../utils/tools.php'; $doc = ['foo' => new MongoDB\BSON\UTCDateTime(new DateTime('2016-10-11 13:34:26.817 UTC'))]; $json = json_encode($doc); echo toJSON(fromPHP($doc)), "\n"; echo $json, "\n"; var_dump(toPHP(fromJSON($json))); ?> ===DONE=== <?php exit(0); ?> --EXPECTF-- { "foo" : { "$date" : 1476192866817 } } {"foo":{"$date":{"$numberLong":"1476192866817"}}} object(stdClass)#%d (%d) { ["foo"]=> object(MongoDB\BSON\UTCDateTime)#%d (%d) { ["milliseconds"]=> string(13) "1476192866817" } } ===DONE===