Serializing an empty object using yii\rest\Serializer

[chriscpty]

This is half a question and half a feature request.

I have an ActiveRecord where one of its fields is an array representing mapping from IDs to values. When this has values, it is serialized as a JSON object (e.g. {"1": "foo", "9": "bar"}. When it is empty, yii\rest\Serializer serializes it to an empty array [] rather than an empty object {}.

You can't avoid this by casting the array to (object) - this seems to be expected behavior (see #12043 , #957 ).

Right now, my solution is to:

• Have an arbitrary class EmptyModel that holds no data
• Whenever my mapping array is empty, replace it with an EmptyModel
• override ArrayHelper::toArray() so that EmptyModels are not serialized (see below)
• override Arrayable::toArray() to use my overridden version of ArrayHelper::toArray().

// in ArrayHelper/MyArrayHelper
public static function toArray($object, $properties = [], $recursive = true, bool $serializeChildObjects = true)
    {
        if (is_array($object)) {
            if ($recursive) {
                foreach ($object as $key => $value) {
                    // before:
                    // if (is_array($value) || is_object($value)) {
                    // replaced with:
                    if (is_array($value) || (is_object($value) && !($value instanceof EmptyModel))) {
                        $object[$key] = static::toArray($value, $properties, true);
                    }
                }
            }

            return $object;
        }

This solution is rather ugly, but I haven't found a better way to do it - is there a pretty way to force a property of a model to always be serialized as an object rather than an array? If not, does anyone have an idea how that could be made possible?

[mtangoo]

Thought of adding custom serializer and attach it to your rest controller? That way you can have granular control as to what you return