The transform examples are all shown on a source class, e.g.

#[Map(target: 'displayPrice', transform: [PriceFormatter::class, 'format'])]
public float $price = 0.0;

https://symfony.com/doc/current/object_mapper.html#transforming-values

If the data is coming from CSV or JSON and does not yet have a class, I'd like to know if it's possible to call a transformer from the target class before the assignment. In particular, I have

{ 
    'price': '$200'
}

And I'd like to transform it to an int without the '$'.

If this is possible, please add an example. If it's not possible, please document that transformers only work from within the source class, not the target class. If that's true, perhaps the #[Map] attribute should throw an error for something like this:

        #[Map(source: 'price'), transform: [self::class, 'cleanupCurrency'])]
        public int $price