(blank? s)
True if s is nil, empty, or contains only whitespace.
user> (clojure.string/blank? nil)
true
user> (clojure.string/blank? "")
true
user> (clojure.string/blank? " ")
true
user> (clojure.string/blank? " a ")
false
user> (clojure.string/blank? false)
true
user> (clojure.string/blank? "\
")
true