Pros of Om

• Simpler and more lightweight than Om Next
• Provides a more straightforward approach to building React-like applications
• Easier to learn and understand for beginners

Cons of Om

• Lacks some of the advanced features and flexibility of Om Next
• May not be suitable for larger, more complex applications
• Potentially less scalable than Om Next

Code Comparison

Om

(defui Counter
  static om/IQuery
  (query [this] [:count])
  static om/IOmRecord
  (initial-state [_] {:count 0})
  Object
  (render [this]
    (let [{:keys [count]} (om/props this)]
      (dom/div nil
        (dom/button #js {:onClick #(om/update-state! this update :count inc)}
          "Increment")
        (dom/span nil (str "Count: " count))))))

(om/root
  Counter
  {:count 0}
  {:target (. js/document (getElementById "app"))})

Om Next

(defui Counter
  static om/IQuery
  (query [this] [:count])
  static om/IOmRecord
  (initial-state [_] {:count 0})
  Object
  (render [this]
    (let [{:keys [count]} (om/props this)]
      (dom/div nil
        (dom/button #js {:onClick #(om/transact! this `[(counter/increment {:count ~count})])}
          "Increment")
        (dom/span nil (str "Count: " count))))))

(def reconciler
  (om/reconciler
    {:state {:counter {:count 0}}
     :parser (om/parser {:read read-counter :mutate mutate-counter})}))

(om/add-root! reconciler Counter (. js/document (getElementById "app")))

The main difference between the two examples is the use of Om Next's reconciler and transaction-based approach, which provides more flexibility and scalability for larger applications.

Pros of re-frame

• Modular Design: re-frame encourages a modular and decoupled architecture, making it easier to manage and scale complex applications.
• Reactive Programming: re-frame's event-driven approach and reactive programming model can lead to more responsive and efficient applications.
• Comprehensive Documentation: re-frame has extensive documentation, providing clear guidance and best practices for building Clojure/ClojureScript applications.

Cons of re-frame

• Steeper Learning Curve: re-frame's architectural patterns and concepts may have a steeper learning curve compared to Om's simpler approach.
• Dependency on re-frame: re-frame is a core dependency for applications built with it, which can make it more difficult to migrate to other libraries or frameworks in the future.
• Verbosity: re-frame's event-driven architecture can sometimes lead to more boilerplate code compared to Om's more straightforward approach.

Code Comparison

Here's a brief comparison of a simple component in Om and re-frame:

Om:

(defui SimpleComponent
  static om/IQuery
  (query [this] [:text])
  Object
  (render [this]
    (let [{:keys [text]} (om/props this)]
      (dom/div nil text))))

(def simple-component (om/factory SimpleComponent))

re-frame:

(defn simple-component []
  [:div (get @(re-frame/subscribe [:text]) 0)])

(re-frame/reg-sub
 :text
 (fn [db _]
   (:text db)))

In the Om example, the component is defined using the defui macro and the om/IQuery protocol is used to specify the data dependencies. In the re-frame example, the component is a simple function that subscribes to the :text subscription, which is defined separately.

Pros of Devcards

• Devcards provides a powerful live development environment, allowing developers to quickly iterate and test their components in isolation.
• The library offers a rich set of features, including support for hot-reloading, interactive documentation, and visual regression testing.
• Devcards integrates well with other ClojureScript libraries, making it a versatile tool for building complex web applications.

Cons of Devcards

• Devcards has a steeper learning curve compared to Om, as it introduces additional concepts and configuration requirements.
• The library may be overkill for smaller projects or simple use cases, where the overhead of setting up Devcards may outweigh the benefits.
• Devcards is primarily focused on the development workflow and may not provide the same level of production-ready features as Om.

Code Comparison

Om:

(defui Counter
  static om/IQuery
  (query [this] [:count])
  static om/IOmRecord
  (initial-state [this] {:count 0})
  Object
  (render [this]
    (let [{:keys [count]} (om/props this)]
      (dom/div nil
        (dom/button #js {:onClick #(om/update-state! this update-in [:count] inc)}
          "Increment")
        (dom/span nil (str "Count: " count))))))

(def counter (om/factory Counter))

Devcards:

(defcard-rg counter
  (fn [data _]
    (r/create-class
     {:reagent-render
      (fn []
        [:div
         [:button {:on-click #(swap! data update :count inc)}
          "Increment"]
         [:span "Count: " (:count @data)]])}))
  {:count 0})