There should be a standard way to get a js-transform fils automatically loaded - for example js_transform.clj. We should only support namespaces transform keys. Unnamespaced transform keys will emit a warning.
As suggested by Thomas Heller reprocess value should now also be allowed to be a namespace qualified symbol. Symbol should point directly at a function, the namespace is auto-required if needed. This is significantly cleaner than having individual `js_transform.clj` files and the all namespace complications it implies.