re-frame/docs/Navigation.md

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## What About Navigation?
How do I switch between different panels of a larger app?
Your `app-db` could have an `:active-panel` key containing an id for the panel being displayed.
When the user does something navigation-ish (selects a tab, a dropdown or something which changes the active panel), then the associated event and dispatch look like this:
```clj
(re-frame/reg-event-db
:set-active-panel
(fn [db [_ value]]
(assoc db :active-panel value)))
(re-frame/dispatch
[:set-active-panel :panel1])
```
A high level reagent view has a subscription to :active-panel and will switch to the associated panel.
```clj
(re-frame/reg-sub
:active-panel
(fn [db _]
(:active-panel db)))
(defn panel1
[]
[:div {:on-click #(re-frame/dispatch [:set-active-panel :panel2])}
"Here" ])
(defn panel2
[]
[:div "There"])
(defn high-level-view
[]
(let [active (re-frame/subscribe [:active-panel])]
(fn []
[:div
[:div.title "Heading"]
(condp = @active ;; or you could look up in a map
:panel1 [panel1]
:panel2 [panel2])])))
```
Continue to [Namespaced Keywords](Namespaced-Keywords.md) to reduce clashes on ids.
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