How to update an element in vector in atom state - clojurescript

Question

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.

Answer 1

(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)}]])

Answer 2

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.