I would like to convert/transform into an empty array if the value is null but when I add the custom method of Joi on my list schema, it doesn't seem to pass by and the value is never converted. I'll always receive null :

Joi.list().allow(null).custom((value) => {
                if (value === null) {
                    return [];
                }

                return value;
            });

Joi.list().allow(null).custom((value) => {
                if (value === null) {
                    return [];
                }

                return [];
            });

Both examples above doesn't work

If value === null, convert to []

Else do nothing

Thanks for your help !