You can avoid it's use through create-class, but it's freely supported and suggested to use it to access the lifecycle callbacks.
Given that there is a supported and suggested pathway to achieving core functionality of the library which involves the use of metadata to define the semantics of your components I stand by my statement. I'm happy to roll back on "the worst thing ever" if a bit of exaggeration is intolerable, but the fact that this exists in the API is a huge wart even given the fact that it's not required.
Weavejester below suggests that use of metadata like this isn't even such a big deal for Clojure, but I cannot agree. In a language with primarily immutable data structures it's just silly to trust metadata as semantics-bearing given that it's invisible, ubiquitous, and often discarded.
> Given that there is a supported and suggested pathway to achieving core functionality of the library which involves the use of metadata to define the semantics of your components I stand by my statement
Sorry, but you are just completely wrong. Have you ever used Reagent? Reagent doesn't require the use of metadata AT ALL, EVER. Much less in some fundamental way, as you claim.
Given that there is a supported and suggested pathway to achieving core functionality of the library which involves the use of metadata to define the semantics of your components I stand by my statement. I'm happy to roll back on "the worst thing ever" if a bit of exaggeration is intolerable, but the fact that this exists in the API is a huge wart even given the fact that it's not required.
Weavejester below suggests that use of metadata like this isn't even such a big deal for Clojure, but I cannot agree. In a language with primarily immutable data structures it's just silly to trust metadata as semantics-bearing given that it's invisible, ubiquitous, and often discarded.
I do really like it on vars, though.