Basic-App-Structure.md

Simpler Apps

To build a re-frame app, you:

• design your app's data structures (data layer)
• write Reagent view functions (domino 5)
• write event handler functions (control layer and/or state transition layer, domino 2)
• write subscription functions (query layer, domino 4)

For simpler apps, you should put code for each layer into separate files:

src
├── core.cljs         <--- entry point, plus history, routing, etc
├── db.cljs           <--- schema, validation, etc  (data layer)
├── views.cljs        <--- reagent views (view layer)
├── events.cljs       <--- event handlers (control/update layer)
└── subs.cljs         <--- subscription handlers  (query layer)

For a living example of this approach, look at the todomvc example.

No really, you should absolutely look at the todomvc example example, as soon as possible. It contains all sorts of tips.

There's A Small Gotcha

If you adopt this structure, there's a gotcha.

events.cljs and subs.cljs will never be required by any other namespaces. To the Google Closure dependency mechanism it appears as if these two namespaces are not needed and it doesn't load them.

And, if the code does not get loaded, the registrations in these namespaces never happen. You'll then be puzzled as to why none of your events handlers are registered.

Once you twig to what's going on, the solution is easy. You must explicitly require both namespaces, events and subs, in your core namespace. Then they'll be loaded and the registrations will occur as that loading happens.

Larger Apps

Assuming your larger apps have multiple "panels" (or "views") which are relatively independent, you might use this structure:

src
├── core.cljs             <--- entry point, plus history, routing, etc
├── panel-1
│   ├── db.cljs           <--- schema, validation, etc  (data layer)
│   ├── subs.cljs         <--- subscription handlers  (query layer)
│   ├── views.cljs        <--- reagent components (view layer)
│   └── events.cljs       <--- event handlers (control/update layer)
├── panel-2
│   ├── db.cljs           <--- schema, validation. etc  (data layer)
│   ├── subs.cljs         <--- subscription handlers  (query layer)
│   ├── views.cljs        <--- reagent components (view layer)
│   └── events.cljs       <--- event handlers (control/update layer)
.
.
└── panel-n

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