feat(codestyle): add state interfaces and use object spread instead o…

…f object assign to type check new state creation in reducers

src/app/core/auth/auth.reducer.ts

@@ -17,25 +17,28 @@ export class ActionAuthLogout implements Action {
 
 export type AuthActions = ActionAuthLogin | ActionAuthLogout;
 
-export const initialState = {
+export const initialState: AuthState = {
   isAuthenticated: false
 };
 
 export const selectorAuth = state => state.auth;
 
-export function authReducer(state = initialState, action: AuthActions) {
+export function authReducer(
+  state: AuthState = initialState,
+  action: AuthActions
+): AuthState {
   switch (action.type) {
     case AuthActionTypes.LOGIN:
-      return Object.assign({}, state, {
-        isAuthenticated: true
-      });
+      return { ...state, isAuthenticated: true };
 
     case AuthActionTypes.LOGOUT:
-      return Object.assign({}, state, {
-        isAuthenticated: false
-      });
+      return { ...state, isAuthenticated: false };
 
     default:
       return state;
   }
 }
+
+export interface AuthState {
+  isAuthenticated: boolean;
+}

src/app/core/meta-reducers/init-state-from-local-storage.reducer.ts

@@ -8,11 +8,7 @@ export function initStateFromLocalStorage(
   return function(state, action) {
     const newState = reducer(state, action);
     if ([INIT.toString(), UPDATE.toString()].includes(action.type)) {
-      return Object.assign(
-        {},
-        newState,
-        LocalStorageService.loadInitialState()
-      );
+      return { ...newState, ...LocalStorageService.loadInitialState() };
     }
     return newState;
   };

src/app/examples/stock-market/stock-market.reducer.ts

@@ -29,38 +29,42 @@ export type StockMarketActions =
   | ActionStockMarketRetrieveSuccess
   | ActionStockMarketRetrieveError;
 
-export const initialState = {
-  symbol: 'GOOGL'
+export const initialState: StockMarketState = {
+  symbol: 'GOOGL',
+  loading: false
 };
 
 export const selectorStocks = state => state.examples.stocks;
 
 export function stockMarketReducer(
-  state = initialState,
+  state: StockMarketState = initialState,
   action: StockMarketActions
-) {
+): StockMarketState {
   switch (action.type) {
     case StockMarketActionTypes.RETRIEVE:
-      return Object.assign({}, state, {
+      return {
+        ...state,
         loading: true,
         stock: null,
         error: null,
         symbol: action.payload.symbol
-      });
+      };
 
     case StockMarketActionTypes.RETRIEVE_SUCCESS:
-      return Object.assign({}, state, {
+      return {
+        ...state,
         loading: false,
         stock: action.payload.stock,
         error: null
-      });
+      };
 
     case StockMarketActionTypes.RETRIEVE_ERROR:
-      return Object.assign({}, state, {
+      return {
+        ...state,
         loading: false,
         stock: null,
         error: action.payload.error
-      });
+      };
 
     default:
       return state;
@@ -74,3 +78,10 @@ export interface Stock {
   ccy: string;
   change: string;
 }
+
+export interface StockMarketState {
+  symbol: string;
+  loading: boolean;
+  stock?: Stock;
+  error?: HttpErrorResponse;
+}

src/app/examples/todos/todos.reducer.ts

@@ -42,9 +42,7 @@ export type TodosActions =
   | ActionTodosFilter
   | ActionTodosPersist;
 
-export type TodosFilter = 'ALL' | 'DONE' | 'ACTIVE';
-
-export const initialState = {
+export const initialState: TodosState = {
   items: [
     { id: uuid(), name: 'Open Todo list example', done: true },
     { id: uuid(), name: 'Check the other examples', done: false },
@@ -59,32 +57,38 @@ export const initialState = {
 
 export const selectorTodos = state => state.examples.todos;
 
-export function todosReducer(state = initialState, action: TodosActions) {
+export function todosReducer(
+  state: TodosState = initialState,
+  action: TodosActions
+): TodosState {
   switch (action.type) {
     case TodosActionTypes.ADD:
-      return Object.assign({}, state, {
+      return {
+        ...state,
         items: state.items.concat({
           id: uuid(),
           name: action.payload.name,
           done: false
         })
-      });
+      };
 
     case TodosActionTypes.TOGGLE:
-      return Object.assign({}, state, {
+      return {
+        ...state,
         items: state.items.map(
           (item: Todo) =>
             item.id === action.payload.id ? { ...item, done: !item.done } : item
         )
-      });
+      };
 
     case TodosActionTypes.REMOVE_DONE:
-      return Object.assign({}, state, {
+      return {
+        ...state,
         items: state.items.filter((item: Todo) => !item.done)
-      });
+      };
 
     case TodosActionTypes.FILTER:
-      return Object.assign({}, state, { filter: action.payload.filter });
+      return { ...state, filter: action.payload.filter };
 
     default:
       return state;
@@ -96,3 +100,10 @@ export interface Todo {
   name: string;
   done: boolean;
 }
+
+export type TodosFilter = 'ALL' | 'DONE' | 'ACTIVE';
+
+export interface TodosState {
+  items: Todo[];
+  filter: TodosFilter;
+}

src/app/settings/settings.reducer.ts

@@ -13,18 +13,25 @@ export class ActionSettingsChangeTheme implements Action {
 
 export type SettingsActions = ActionSettingsChangeTheme;
 
-export const initialState = {
+export const initialState: SettingsState = {
   theme: 'DEFAULT-THEME'
 };
 
 export const selectorSettings = state => state.settings || { theme: '' };
 
-export function settingsReducer(state = initialState, action: SettingsActions) {
+export function settingsReducer(
+  state: SettingsState = initialState,
+  action: SettingsActions
+): SettingsState {
   switch (action.type) {
     case SettingsActionTypes.CHANGE_THEME:
-      return { theme: action.payload.theme };
+      return { ...state, theme: action.payload.theme };
 
     default:
       return state;
   }
 }
+
+export interface SettingsState {
+  theme: string;
+}