CODEWITHSUNDEEP
clojurescript
soeik
soeik

Reputation: 925

How to update an element in vector in atom state

I'm trying to create kind of todo list with ClojureScript and reagent framework. I defined app state as atom:

(def app-state
  (r/atom
   {:count 3
    :todolist
    [{:id 0 :text "Start learning mindcontrol" :finished true}
     {:id 1 :text "Read a book 'Debugging JS in IE11 without pain'" :finished false}
     {:id 2 :text "Become invisible for a while" :finished false}]}))

Have a function to update todo list:

(defn update-todolist [f & args]
  (apply swap! app-state update-in [:todolist] f args))

And function toggle todo:

(defn toggle-todo [todo]
  (update-todolist update-in [2] assoc :finished true))

Here I'm updating vector element directly by its index right now.

I'm rendering every item with this function:

(defn item [todo]
  ^{:key (:id todo)}
  [:div
   [:span {:class "item-text"} (:text todo)]
   [:i {:class (str "ti-check " (if (:finished todo) "checked" "unchecked"))
        :on-click #(toggle-todo (assoc todo :finished true))}]])

Here I'm passing updated todo but it's not correct to pass always true. Probably it would be enough to pass its index and it will solve my problem, but I have no idea how to do this.

Upvotes: 0

Views: 143

Answers (2)

Caleb Macdonald Black
Caleb Macdonald Black

Reputation: 1582

(def app-state
  (r/atom
   {:count 3
    :todolist
    [{:id 0 :text "Start learning mindcontrol" :finished true}
     {:id 1 :text "Read a book 'Debugging JS in IE11 without pain'" :finished false}
     {:id 2 :text "Become invisible for a while" :finished false}]}))


(defn update-todolist [f & args]
  (apply swap! app-state update-in [:todolist] f args))


(defn toggle-todo [todo]
  (swap! app-state update-in [:todolist (:id todo) :finished] not))


(defn item [todo]
  ^{:key (:id todo)}
  [:div
   [:span {:class "item-text"} (:text todo)]
   [:i {:class (str "ti-check " (if (:finished todo) "checked" "unchecked"))
        :on-click #(toggle-todo todo)}]])

Upvotes: 2

Alan Thompson
Alan Thompson

Reputation: 29984

To toggle the value of the :finished key, just use not:

(swap! app-state update-in [:todolist 2 :finished] not) => 

    {:count 3,
     :todolist
       [{:id 0, :text "Start learning mindcontrol", 
                :finished true}
        {:id 1, :text "Read a book 'Debugging JS in IE11 without pain'",
                :finished false}
        {:id 2, :text "Become invisible for a while", 
                :finished true}]}

However, this does not tell you how the index 2 corresponds with the map that has :id 2 inside it.

Upvotes: 0

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