Refactoring to take advantage of Immer's drafts

src/store/map.ts

@@ -60,12 +60,29 @@ const nbTilesY = _.ceil(mapState.viewport.height / tileSize) + 4;
 
 */
 
-const computeStateFromScope = (scope: MapScope) => {
-  const newScope = _.cloneDeep(scope);
-  let state: MapState = {} as MapState;
-  state.scope = newScope;
-  state.tiles = {} as TilesDescription;
-  state.slippy = {} as SlippyState;
+let initialMapState: MapState = {
+  scope: initialMapScope,
+  slippy: {
+    scale: 1,
+    translation: {
+      x: 0,
+      y: 0,
+    },
+  },
+  tiles: {
+    first: {
+      x: 0,
+      y: 0,
+    },
+    nb: {
+      x: 0,
+      y: 0,
+    },
+    zoom: 0,
+  },
+};
+
+const evaluateStateFromScope = (state: MapState) => {
   state.tiles.zoom = _.round(state.scope.zoom);
   const softZoom = state.scope.zoom - state.tiles.zoom;
   state.slippy.scale = 2 ** softZoom;
@@ -94,18 +111,20 @@ const computeStateFromScope = (scope: MapScope) => {
     x: tilesCenterTargetLocation.x - tilesCenterActualLocation.x,
     y: tilesCenterTargetLocation.y - tilesCenterActualLocation.y,
   };
-
-  return state;
 };
 
-const initialMapState: MapState = computeStateFromScope(initialMapScope);
+evaluateStateFromScope(initialMapState);
+
+const reevaluateState = (state: MapState) => {};
+
+
 
 const mapSlice = createSlice({
   name: 'map',
   initialState: initialMapState,
   reducers: {
     resize: (state) => {
-      return computeStateFromScope(state.scope);
+      evaluateStateFromScope(state);
     },
     shift: (state, action) => {
       state.slippy.translation = {