I usually use identity as a predicate for functions such as filter,
drop-while, take-while, etc.
Consider this silly example: imagine you had an operation that fetches
stuff from a resource (DB, network, etc.) and that upon failing it
returns nil. Additionally, imagine that you're interested in running
this operation for several resources and keeping those values which
didn't fail. You can do so with identity:
user=> (defn my-operation-that-might-fail [x]
(if (= x "foo") x nil))
#'user/my-operation-that-might-fail
user=> (def some-values ["bar" "foo" "baz"])
#'user/some-values
user=> (filter identity (map your-pred some-values))
("foo")
user=>
and you have your single operation that didn't fail.
My 0.5cts.
U
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