Doctrine\ODM\MongoDB\Persisters\PersistenceBuilder::prepareValue PHP Method

    public function prepareValue(array $mapping, $value)
    {
        if ($value === null) {
            return null;
        }
        if ($mapping['type'] === 'many') {
            $prepared = null;
            if ($value) {
                $oneMapping = $mapping;
                $oneMapping['type'] = 'one';
                $prepared = array();
                foreach ($value as $rawValue) {
                    $prepared[] = $this->prepareValue($oneMapping, $rawValue);
                }
            }
        } elseif (isset($mapping['embedded'])) {
            $prepared = $this->prepareEmbeddedDocValue($mapping, $value);
        } elseif (isset($mapping['reference'])) {
            $prepared = $this->prepareReferencedDocValue($mapping, $value);
        } else {
            $prepared = Type::getType($mapping['type'])->convertToDatabaseValue($value);
        }
        return $prepared;
    }