Using atomWithHash to enable back/forward actions.

src/App.tsx

@@ -22,32 +22,46 @@ import '@ionic/react/css/display.css';
 import './theme/variables.css';
 import LiveMap from './components/map/LiveMap';
 
+import { useAtom } from 'jotai';
+import { atomWithHash } from 'jotai/utils';
+import { MapScope } from './components/map/types';
+import { debounce } from 'lodash';
+
 setupIonicReact();
 
+const initialScope: MapScope = {
+  center: { lat: -37.8403508, lon: 77.5539501 },
+  zoom: 13,
+  tileProvider: 'osm',
+};
+const scopeAtom = atomWithHash('scope', initialScope);
+
 /**
  *
  * @returns The root app component
  */
-const App: React.FC = () => (
+const App: React.FC = () => {
-  <IonApp>
+  const [scope, setScope] = useAtom(scopeAtom);
-    <IonReactRouter>
+
-      <IonRouterOutlet>
+  console.log(`App, scope: ${JSON.stringify(scope)}`);
-        <Route exact path='/home'>
+  return (
-          <LiveMap
+    <IonApp>
-            scope={{
+      <IonReactRouter>
-              center: { lat: -37.8403508, lon: 77.5539501 },
+        <IonRouterOutlet>
-              zoom: 13,
+          <Route exact path='/home'>
-              tileProvider: 'osm',
+            <LiveMap
-            }}
+              scope={scope}
-            numberOfTiledLayers={5}
+              setScope={debounce(setScope, 1000)}
-          />
+              numberOfTiledLayers={5}
-        </Route>
+            />
-        <Route exact path='/'>
+          </Route>
-          <Redirect to='/home' />
+          <Route exact path='/'>
-        </Route>
+            <Redirect to='/home' />
-      </IonRouterOutlet>
+          </Route>
-    </IonReactRouter>
+        </IonRouterOutlet>
-  </IonApp>
+      </IonReactRouter>
-);
+    </IonApp>
+  );
+};
 
 export default App;

src/components/map/LiveMap.tsx

@@ -1,4 +1,4 @@
-import react, { useState } from 'react';
+import react, { useEffect, useState } from 'react';
 import { MapScope, Point } from './types';
 import Map from './Map';
 import Handlers from './Handlers';
@@ -31,26 +31,33 @@ export interface Transformation {
 }
 
 export interface LiveMapProperties {
+  /** The initial map's scope */
   scope: MapScope;
+  /** The number of tiled layers (default to 1) */
   numberOfTiledLayers?: number;
+  /** If provided, a function to call when the scope is updated. */
+  setScope?: (scope: MapScope) => void;
 }
 
 /**
- * 
+ *
- * @param props 
+ * @param props
  * @returns A `<LiveMap>` component.
- * 
+ *
  * A `<LiveMap>` is a wrapper around a {@link components/map/Map!Map} component which updates the `<Map>`'s scope according to user's mouse, wheel and touch events.
- * 
+ *
  * To do so, `<LiveMap>` embeds a `<Map>` component together with a {@link components/map/Handlers!Handlers} component which listens to user's event.
- * 
+ *
  * The main task of `<LiveMap>` components is thus to translate {@link Transformation}s delivered by `<Handler>` in pixels into geographical coordinates.
  */
 export const LiveMap: react.FC<LiveMapProperties> = (
   props: LiveMapProperties
 ) => {
   const [scope, setScope] = useState(props.scope);
-  // console.log(`LiveMap rendering: ${JSON.stringify(scope)}`);
+  useEffect(() => {
+    setScope(props.scope);
+  }, [props.scope]);
+  console.log(`LiveMap rendering: ${JSON.stringify(scope)}`);
   const transform = (t: Transformation) => {
     const deltaZoom = t.deltaZoom === null ? 1 : t.deltaZoom;
     const deltaZoomLevel = Math.log2(deltaZoom);
@@ -114,6 +121,9 @@ export const LiveMap: react.FC<LiveMapProperties> = (
     //   }, delta lon: ${newScope.center.lon - scope.center.lon}`
     // );
     setScope(newScope);
+    if (props.setScope !== undefined) {
+      props.setScope(newScope);
+    }
   };
 
   return (