How to cast a string into an array using Yup

So whenever I receive a string I want to store it as an array. But I've got no luck so far, i tried to do with cast and with transform. I just need some clarity to get the things going.

Is transform and cast the same thing? How to cast a string into an array using Yup?

const schema = yup.object().shape({
        types: yup
           .array('type must be an array.')
           .of(
                yup
                   .string('the array must contains only strings.')
                   .transform(value =>
                      typeof value === 'string' || myVar instanceof 'string'
                           ? [value]
                           : value,
                   )
                   .matches(/(writer|artist)/, null),
           )
           .min(1, 'Need to provide at least one type')
           .max(2, 'Can not provide more than two types'),
        name: yup
           .string('name must be a string.')
           .min(3, 'too short'),
      
    });

let obj = {
      name: 'Kentarou Kishima',
      types: 'artist',
}
//returns ValidationError
obj = schema.cast(obj, { stripUnknown: true });

//trying to just validate results in the same error
schema
        .validate(obj)
        .then(() => {     
              
            next();
        })
        .catch(function (e) {
            console.log(e);
            return something;
        });

ValidationError: types must be a array type, but the final value was: null (cast from the value "artist")

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