Add Redux and reducers.

Load i18n files and add dayjs.

src/redux/reducers/typing.ts

@@ -0,0 +1,46 @@
+export type TypingUser = { id: string, started: number };
+export type Typing = { [key: string]: TypingUser[] };
+
+export type TypingAction =
+    | { type: undefined }
+    | {
+          type: "TYPING_START";
+          channel: string;
+          user: string;
+      }
+    | {
+          type: "TYPING_STOP";
+          channel: string;
+          user: string;
+      }
+    | {
+          type: "RESET";
+      };
+
+export function typing(state: Typing = {}, action: TypingAction): Typing {
+    switch (action.type) {
+        case "TYPING_START":
+            return {
+                ...state,
+                [action.channel]: [
+                    ...(state[action.channel] ?? []).filter(
+                        x => x.id !== action.user
+                    ),
+                    {
+                        id: action.user,
+                        started: + new Date()
+                    }
+                ]
+            };
+        case "TYPING_STOP":
+            return {
+                ...state,
+                [action.channel]:
+                    state[action.channel]?.filter(x => x.id !== action.user) ?? []
+            };
+        case "RESET":
+            return {};
+        default:
+            return state;
+    }
+}