with_prevent_default t handles the event using handler t, and additionally prevents the default handler.
val only_handle_if : ?prevent_default:unit->Condition.t->t->t
only_handle_if ?prevent_default cond t handles the event using handler t if cond ev evaluates to true (and additionally prevent the default handler if prevent_default is passed in), and does nothing otherwise.
val handle_by_case : ?prevent_default:unit->(Condition.t * t) list->t
handle_by_case is similar to only_handle_if, but allows the user to provide a list of handlers and their respective conditions instead of a single one. If multiple handlers' conditions evaluate to true, the first one is used.