Basic scaffold for managing equiped items

src/lib/state.ts

@@ -0,0 +1,64 @@
+import type { EquipedItem, Item, ItemId } from "./types";
+
+export type State = {
+  equipedItems: EquipedItem[];
+  bisList: ItemId[];
+};
+
+export type Action =
+  | {
+      action: "equipItem";
+      item: Item;
+    }
+  | {
+      action: "unequipItem";
+      item: Item;
+    };
+
+export const reducer = (state: State, action: Action): State => {
+  switch (action.action) {
+    case "equipItem":
+      return {
+        ...state,
+        equipedItems: [
+          ...state.equipedItems,
+          {
+            id: action.item.id,
+            quality: "champion", // Default quality, can be changed later
+          },
+        ],
+      };
+    case "unequipItem":
+      return {
+        ...state,
+        equipedItems: state.equipedItems.filter(
+          (item) => item.id !== action.item.id,
+        ),
+      };
+  }
+};
+
+export type LoadingAction<S> = {
+  action: "loadState";
+  state: S;
+};
+
+function isLoadingAction<A, S>(
+  action: A | LoadingAction<S>,
+): action is LoadingAction<S> {
+  return (action as LoadingAction<S>).action === "loadState";
+}
+
+export const withLoadingAction =
+  <S, A>(reducer: (state: S, action: A) => S) =>
+  (state: S | "loading", action: A | LoadingAction<S>): S | "loading" => {
+    if (state !== "loading" && !isLoadingAction(action)) {
+      return reducer(state, action);
+    }
+
+    if (state === "loading" && isLoadingAction(action)) {
+      return action.state;
+    }
+
+    return state;
+  };