@@ -1,12 +1,105 @@
+/*
+# Example with state persistance
+
+Require to have
+- @reason-react-native/storage (ReactNativeAsyncStorage)
+- reason-future
+
+Require to define your own
+
+- <RootNavigator />
+- <BootSplash />
+
+
+```reason
+open Belt;
+open ReactNative;
+
+// @todo
+// <RootNavigator />
+// <Bootsplash />
+
+type navigationState;
+let navigationStateStorageKey = "react-navigation:state";
+
+[@react.component]
+let app = () => {
+let (initialStateContainer, setInitialState) = React.useState(() => None);
+
+React.useEffect1(
+() => {
+if (initialStateContainer->Option.isNone) {
+ReactNativeAsyncStorage.getItem(navigationStateStorageKey)
+->FutureJs.fromPromise(error => {
+// @todo ?
+Js.log2("Restoring Navigation State: ", error);
+error;
+})
+->Future.tap(res => {
+switch (res) {
+| Result.Ok(jsonState) =>
+switch (jsonState->Js.Null.toOption) {
+| Some(jsonState) =>
+switch (Js.Json.parseExn(jsonState)) {
+| state =>
+setInitialState(_ => Some(Some(state)));
+| exception _ =>
+Js.log2(
+"Restoring Navigation State: unable to decode valid json",
+jsonState,
+);
+setInitialState(_ => Some(None));
+}
+| None => setInitialState(_ => Some(None))
+};
+| Result.Error(e) =>
+Js.log2(
+"Restoring Navigation State: unable to get json state",
+e,
+);
+setInitialState(_ => Some(None));
+};
+})
+->ignore;
+};
+None;
+},
+[|initialStateContainer|],
+);
+
+let isReady = initialStateContainer->Option.isSome;
+<>
+{initialStateContainer
+->Option.map(initialState =>
+<Native.NavigationNativeContainer
+?initialState
+onStateChange={state => {
+let maybeJsonState = Js.Json.stringifyAny(state);
+switch (maybeJsonState) {
+| Some(jsonState) =>
+AsyncStorage.setItem(navigationStateStorageKey, jsonState)
+->ignore
+| None => Js.log("Unable to stringify navigation state")
+};
+}}>
+<RootNavigator />
+</Native.NavigationNativeContainer>
+)
+->Option.getWithDefault(React.null)}
+<Bootsplash isReady />
+</>;
+};
+```
+*/
+
 module NavigationNativeContainer = {
-//TODO
-type initialState;
-type navigationState;
+type state = Js.Json.t;
+type navigationState = state => unit;
 
 [@bs.module "@react-navigation/native"] [@react.component]
 external make:
 (
-~initialState: initialState=?,
+~initialState: state=?,
 ~onStateChange: navigationState=?,
 ~children: React.element
 ) =>