registration: redesign email verification page (#8554)

src/components/structures/auth/header/AuthHeaderProvider.tsx

@@ -0,0 +1,52 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { isEqual } from "lodash";
+import React, { ComponentProps, PropsWithChildren, Reducer, useReducer } from "react";
+
+import { AuthHeaderContext } from "./AuthHeaderContext";
+import { AuthHeaderModifier } from "./AuthHeaderModifier";
+
+export enum AuthHeaderActionType {
+    Add,
+    Remove
+}
+
+interface AuthHeaderAction {
+    type: AuthHeaderActionType;
+    value: ComponentProps<typeof AuthHeaderModifier>;
+}
+
+export type AuthHeaderReducer = Reducer<ComponentProps<typeof AuthHeaderModifier>[], AuthHeaderAction>;
+
+export function AuthHeaderProvider({ children }: PropsWithChildren<{}>) {
+    const [state, dispatch] = useReducer<AuthHeaderReducer>(
+        (state: ComponentProps<typeof AuthHeaderModifier>[], action: AuthHeaderAction) => {
+            switch (action.type) {
+                case AuthHeaderActionType.Add:
+                    return [action.value, ...state];
+                case AuthHeaderActionType.Remove:
+                    return (state.length && isEqual(state[0], action.value)) ? state.slice(1) : state;
+            }
+        },
+        [] as ComponentProps<typeof AuthHeaderModifier>[],
+    );
+    return (
+        <AuthHeaderContext.Provider value={{ state, dispatch }}>
+            { children }
+        </AuthHeaderContext.Provider>
+    );
+}