trivial-mobx-todo.js

var state = mobx.observable({
    todos : [],
    visibilityFilter : "ALL",
    
    addTodoItem : action(function (text, completed) {
      this.todos.push({text, completed})
    }),
    
    setVisibilityFilter : action(function (filter) {
      this.visibilityFilter = filter;
    })
});

trivial-reagent-todo.cljs

(def state (r/atom {
                     :todos [] 
                     :visibility-filter :all}))

(defn add-todo-item [text completed] 
    (swap! state update-in [:todos] conj {:text text :completed completed}))

(defn set-visibility-filter [filter] 
    (swap! state assoc :visibility-filter filter))