add jest testing

.babelrc

@@ -0,0 +1,3 @@
+{
+  "presets": ["@babel/preset-env", "@babel/preset-typescript"]
+}

.eslintrc.js

@@ -1,7 +1,7 @@
 module.exports = {
   root: true,
   parser: '@typescript-eslint/parser',
-  plugins: ['@typescript-eslint'],
+  plugins: ['@typescript-eslint', "jest"],
   extends: [
     'eslint:recommended',
     'plugin:@typescript-eslint/recommended',
@@ -27,6 +27,7 @@ module.exports = {
     "@typescript-eslint/restrict-template-expressions": "off",
     "@typescript-eslint/unbound-method": "off",
     "@typescript-eslint/quotes": "warn",
+    "@typescript-eslint/no-unused-expressions": "off",
     "arrow-parens": "off",
     "class-methods-use-this": "off",
     "func-names": "off",
@@ -38,11 +39,14 @@ module.exports = {
     "no-continue": "off",
     "no-plusplus": "off",
     "object-curly-newline": "off",
+    "no-alert": "off",
+    "no-restricted-globals": "off",
   },
   env: {
     browser: true,
     node: true,
     es6: true,
+    jest: true,
   },
-  ignorePatterns: ['.eslintrc.js', 'deploy-config.js']
+  ignorePatterns: ['.eslintrc.js', 'deploy-config.js'],
 };

package.json

@@ -3,21 +3,28 @@
   "version": "1.0.0",
   "main": "index.js",
   "devDependencies": {
+    "@babel/preset-env": "^7.18.6",
+    "@babel/preset-typescript": "^7.18.6",
     "@types/happypack": "^5.0.2",
     "@types/html-webpack-plugin": "^3.2.6",
+    "@types/jest": "^28.1.4",
     "@types/node": "^17.0.40",
     "@types/sass-loader": "^8.0.3",
     "@types/webpack": "^5.28.0",
     "@typescript-eslint/eslint-plugin": "^5.27.1",
     "@typescript-eslint/parser": "^5.27.1",
+    "babel-jest": "^28.1.2",
     "copy-webpack-plugin": "^11.0.0",
     "css-loader": "^6.7.1",
     "dotenv": "^16.0.1",
     "eslint": "^8.17.0",
     "eslint-config-airbnb": "^19.0.4",
     "eslint-config-airbnb-typescript": "^17.0.0",
+    "eslint-plugin-jest": "^26.5.3",
     "eslint-webpack-plugin": "^3.1.1",
     "html-webpack-plugin": "^5.5.0",
+    "jest": "^28.1.2",
+    "jest-environment-jsdom": "^28.1.2",
     "mini-css-extract-plugin": "^2.6.0",
     "sass": "^1.52.2",
     "sass-loader": "^13.0.0",
@@ -38,7 +45,9 @@
   "scripts": {
     "start": "webpack serve --mode=development",
     "build": "webpack --mode=production",
-    "deploy": "node deploy-config"
+    "deploy": "node deploy-config",
+    "test": "npx jest",
+    "test-watch": "npx jest --watch"
   },
   "keywords": [],
   "author": "ksv741",
@@ -52,5 +61,10 @@
   "module": "true",
   "dependencies": {
     "normalize.css": "^8.0.1"
+  },
+  "jest": {
+    "transform": {
+      "\\.[jt]sx?$": "babel-jest"
+    }
   }
 }

src/components/excel/Excel.ts

@@ -1,4 +1,4 @@
-import { Store } from 'core/createStore';
+import { Store } from 'core/store/createStore';
 import { $ } from 'core/dom';
 import { Emitter } from 'core/Emitter';
 import { ExcelComponent } from 'core/ExcelComponent';

src/core/ExcelComponent.ts

@@ -1,8 +1,8 @@
 import { ActionType } from 'redux/types';
-import { Store } from './createStore';
-import { Dom } from './dom';
-import { DomListener } from './DomListener';
-import { Emitter } from './Emitter';
+import { Store } from 'core/store/createStore';
+import { Dom } from 'core/dom';
+import { DomListener } from 'core/DomListener';
+import { Emitter } from 'core/Emitter';
 
 interface ExcelComponentClass {
   toHTML: () => string;

src/core/StoreSubscriber.ts

@@ -1,5 +1,5 @@
 import { StateType } from 'redux/types';
-import { Store } from './createStore';
+import { Store } from './store/createStore';
 import { isEqual } from './utils';
 
 export class StoreSubscriber {

src/core/dom.ts

@@ -1,6 +1,6 @@
 import { initialStyleState } from '../constants';
 
-type SelectorType = string | HTMLElement;
+export type SelectorType = string | HTMLElement;
 
 export interface DomClass {
   html(html?: string): string | DomClass;

src/core/routes/Router.spec.js

@@ -0,0 +1,38 @@
+/**
+ * @jest-environment jsdom
+ */
+
+import { Router } from './router';
+import { Page } from '../Page';
+
+class DashboardPage extends Page {
+  getRoot() {
+    const root = document.createElement('div');
+    root.innerHTML = 'dashboard';
+
+    return root;
+  }
+}
+class ExcelPage extends Page {}
+
+describe('Router:', () => {
+  let router;
+  let $root;
+
+  beforeEach(() => {
+    $root = document.createElement('div');
+    router = new Router($root, {
+      excel: ExcelPage,
+      dashboard: DashboardPage,
+    });
+  });
+
+  test('should be defined', () => {
+    expect(router).toBeDefined();
+  });
+
+  test('should render Dasboard Page', () => {
+    router.changePageHandler();
+    expect($root.innerHTML).toBe('<div>dashboard</div>');
+  });
+});

src/core/routes/router.ts

@@ -1,17 +1,19 @@
 import { DashboardPage } from 'pages/DashboardPage';
 import { ExcelPage } from 'pages/ExcelPage';
-import { $, Dom } from 'core/dom';
+import { $, Dom, SelectorType } from 'core/dom';
 import { ActiveRoute } from './ActiveRoute';
 
+type RoutesType = {
+  dashboard: DashboardPage
+  excel: ExcelPage
+};
+
 export class Router {
   private $placeholder: Dom;
-  private routes: {
-    dashboard: DashboardPage
-    excel: ExcelPage
-  };
-  private page: DashboardPage | ExcelPage;
+  private routes: RoutesType;
+  private page: DashboardPage | ExcelPage | null;
 
-  constructor(selector: string, routes: any) {
+  constructor(selector: SelectorType, routes: RoutesType) {
     if (!selector) throw new Error('Selector not provided');
 
     this.$placeholder = $(selector);
@@ -47,8 +49,8 @@ export class Router {
     // @ts-ignore
     this.page = new Page(ActiveRoute.param);
 
-    this.$placeholder.append(this.page.getRoot());
-    this.page.afterRender();
+    this.$placeholder.append(this.page?.getRoot());
+    this.page?.afterRender();
   }
 
   destroy() {

src/core/store/createStore.spec.js

@@ -0,0 +1,77 @@
+import { Store } from './createStore';
+
+const initialState = {
+  count: 0,
+};
+
+const reducer = (state, action) => {
+  if (action.type === 'ADD') {
+    return { ...state, count: state.count + 1 };
+  }
+
+  return state;
+};
+
+describe('Create store', () => {
+  let store;
+  let handler;
+
+  beforeEach(() => {
+    store = new Store(reducer, initialState);
+    handler = jest.fn();
+  });
+
+  test('should return store object', () => {
+    expect(store).toBeDefined();
+    expect(store.dispatch).toBeDefined();
+    expect(store.subscribe).toBeDefined();
+    expect(store.getState).not.toBeUndefined();
+  });
+
+  test('should return object as a state', () => {
+    expect(store.getState()).toBeInstanceOf(Object);
+  });
+
+  test('should return default state', () => {
+    expect(store.getState()).toEqual(initialState);
+  });
+
+  test('should change state if actions exist', () => {
+    store.dispatch({ type: 'ADD' });
+    expect(store.getState().count).toBe(1);
+  });
+
+  test("should NOT change state if actions don't exist", () => {
+    store.dispatch({ type: 'NOT_EXISTING_TYPE' });
+    expect(store.getState().count).toBe(0);
+  });
+
+  test('should call subscriber', () => {
+    store.subscribe(handler);
+    store.dispatch({ type: 'ADD' });
+
+    expect(handler).toHaveBeenCalled();
+    expect(handler).toHaveBeenCalledWith(store.getState());
+  });
+
+  test('should NOT call sub if unsubscribe', () => {
+    const unsub = store.subscribe(handler);
+    unsub.unsubscribe();
+    store.dispatch({ type: 'ADD' });
+
+    expect(handler).not.toHaveBeenCalled();
+  });
+
+  test('should dispatch in async way', () => {
+    return new Promise(resolve => {
+      setTimeout(() => {
+        store.dispatch({ type: 'ADD' });
+      }, 500);
+
+      setTimeout(() => {
+        expect(store.getState().count).toBe(1);
+        resolve();
+      }, 1000);
+    });
+  });
+});

src/core/store/createStore.ts

@@ -1,4 +1,4 @@
-import { ActionType, ReducerType, StateType, SubscribeType } from '../redux/types';
+import { ActionType, ReducerType, StateType, SubscribeType } from 'redux/types';
 
 export class Store {
   state: StateType;

src/pages/ExcelPage.ts

@@ -3,7 +3,7 @@ import { Formula } from 'components/formula/Formula';
 import { Header } from 'components/header/Header';
 import { Table } from 'components/table/Table';
 import { Toolbar } from 'components/toolbar/Toolbar';
-import { Store } from 'core/createStore';
+import { Store } from 'core/store/createStore';
 import { Page } from 'core/Page';
 import { debounce, storage } from 'core/utils';
 import { rootReducer } from 'redux/rootReducer';

tsconfig.json

@@ -19,7 +19,8 @@
     "compilerOptions": {
       "module": "CommonJS",
       "strictPropertyInitialization": true,
-      "sourceMap": true
+      "sourceMap": true,
+      "exclude": ["node_modules"]
     }
   },
   "exclude": ["node_modules"],