Draw frozen combat in the new UI.

https://github.com/dcs-liberation/dcs_liberation/issues/2039

client/src/api/combatSlice.ts

@@ -0,0 +1,42 @@
+import { RootState } from "../app/store";
+import Combat from "./combat";
+import { PayloadAction, createSlice } from "@reduxjs/toolkit";
+
+interface CombatState {
+  combat: { [key: string]: Combat };
+}
+
+const initialState: CombatState = {
+  combat: {},
+};
+
+export const combatSlice = createSlice({
+  name: "combat",
+  initialState,
+  reducers: {
+    setCombat: (state, action: PayloadAction<Combat[]>) => {
+      state.combat = {};
+      for (const combat of action.payload) {
+        state.combat[combat.id] = combat;
+      }
+    },
+    newCombat: (state, action: PayloadAction<Combat>) => {
+      const combat = action.payload;
+      state.combat[combat.id] = combat;
+    },
+    updateCombat: (state, action: PayloadAction<Combat>) => {
+      const combat = action.payload;
+      state.combat[combat.id] = combat;
+    },
+    endCombat: (state, action: PayloadAction<string>) => {
+      delete state.combat[action.payload];
+    },
+  },
+});
+
+export const { setCombat, newCombat, updateCombat, endCombat } =
+  combatSlice.actions;
+
+export const selectCombat = (state: RootState) => state.combat;
+
+export default combatSlice.reducer;