clojurescript 试剂交换!原子否定原子值

Question

我试图反转试剂原子的值变化

(def changeval(reagent/atom 0))
...
...
[:input {:type "button" :value "Invert!"
            :on-click #(swap! changeval(not= changeval0 ) ) }]

没有任何反应，我怎样才能使 changeval = NOT(changeval)

Answer 1

检查 swap! 的签名功能:

(swap! atom f)

(swap! atom f x)

(swap! atom f x y)

(swap! atom f x y & args)

Atomically swaps the value of atom to be: (apply f current-value-of-atom args). Note that f may be called multiple times, and thus should be free of side effects. Returns the value that was swapped in.

因此要否定原子中的值(它与 Clojure 和 Reagent 的原子一样工作)使用 not 函数(在您的情况下，不会有额外的参数，因为您将只使用原子的当前值):

(def value (atom true))

(swap! value not)
;; => false

(swap! value not)
;; => true