Replace legacy counter example with latest CRA+JS template

Author: markerikson

examples/counter/.gitignore

@@ -1,11 +1,23 @@
-# See http://help.github.com/ignore-files/ for more about ignoring files.
+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
 
 # dependencies
-node_modules
+/node_modules
+/.pnp
+.pnp.js
+
+# testing
+/coverage
 
 # production
-build
+/build
 
 # misc
 .DS_Store
-npm-debug.log
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*

examples/counter/README.md

@@ -1,35 +1,46 @@
-# Redux Counter Example
+# Getting Started with Create React App and Redux
 
-This project template was built with [Create React App](https://github.com/facebookincubator/create-react-app), which provides a simple way to start React projects with no build configuration needed.
-
-Projects built with Create-React-App include support for ES6 syntax, as well as several unofficial / not-yet-final forms of Javascript syntax such as Class Properties and JSX. See the list of [language features and polyfills supported by Create-React-App](https://github.com/facebookincubator/create-react-app/blob/master/packages/react-scripts/template/README.md#supported-language-features-and-polyfills) for more information.
+This project was bootstrapped with [Create React App](https://github.com/facebook/create-react-app), using the [Redux](https://redux.js.org/) and [Redux Toolkit](https://redux-toolkit.js.org/) template.
 
 ## Available Scripts
 
 In the project directory, you can run:
 
 ### `npm start`
 
-Runs the app in the development mode.<br>
-Open [http://localhost:3000](http://localhost:3000) to view it in the browser.
+Runs the app in the development mode.\
+Open [http://localhost:3000](http://localhost:3000) to view it in your browser.
+
+The page will reload when you make changes.\
+You may also see any lint errors in the console.
 
-The page will reload if you make edits.<br>
-You will also see any lint errors in the console.
+### `npm test`
+
+Launches the test runner in the interactive watch mode.\
+See the section about [running tests](https://facebook.github.io/create-react-app/docs/running-tests) for more information.
 
 ### `npm run build`
 
-Builds the app for production to the `build` folder.<br>
+Builds the app for production to the `build` folder.\
 It correctly bundles React in production mode and optimizes the build for the best performance.
 
-The build is minified and the filenames include the hashes.<br>
+The build is minified and the filenames include the hashes.\
 Your app is ready to be deployed!
 
+See the section about [deployment](https://facebook.github.io/create-react-app/docs/deployment) for more information.
+
 ### `npm run eject`
 
-**Note: this is a one-way operation. Once you `eject`, you can’t go back!**
+**Note: this is a one-way operation. Once you `eject`, you can't go back!**
+
+If you aren't satisfied with the build tool and configuration choices, you can `eject` at any time. This command will remove the single build dependency from your project.
+
+Instead, it will copy all the configuration files and the transitive dependencies (webpack, Babel, ESLint, etc) right into your project so you have full control over them. All of the commands except `eject` will still work, but they will point to the copied scripts so you can tweak them. At this point you're on your own.
+
+You don't have to ever use `eject`. The curated feature set is suitable for small and middle deployments, and you shouldn't feel obligated to use this feature. However we understand that this tool wouldn't be useful if you couldn't customize it when you are ready for it.
 
-If you aren’t satisfied with the build tool and configuration choices, you can `eject` at any time. This command will remove the single build dependency from your project.
+## Learn More
 
-Instead, it will copy all the configuration files and the transitive dependencies (Webpack, Babel, ESLint, etc) right into your project so you have full control over them. All of the commands except `eject` will still work, but they will point to the copied scripts so you can tweak them. At this point you’re on your own.
+You can learn more in the [Create React App documentation](https://facebook.github.io/create-react-app/docs/getting-started).
 
-You don’t have to ever use `eject`. The curated feature set is suitable for small and middle deployments, and you shouldn’t feel obligated to use this feature. However we understand that this tool wouldn’t be useful if you couldn’t customize it when you are ready for it.
+To learn React, check out the [React documentation](https://reactjs.org/).

examples/counter/package-lock.json

@@ -1,29 +1,40 @@
 {
   "name": "counter",
-  "version": "0.0.1",
+  "version": "0.1.0",
   "private": true,
-  "devDependencies": {
-    "enzyme": "^3.11.0",
-    "enzyme-adapter-react-16": "^1.15.2",
-    "react-scripts": "^4.0.3"
-  },
   "dependencies": {
-    "prop-types": "^15.7.2",
-    "react": "^17.0.2",
-    "react-dom": "^17.0.2",
-    "react-redux": "^7.2.0",
-    "redux": "^4.0.5"
+    "@reduxjs/toolkit": "^1.8.3",
+    "@testing-library/jest-dom": "^5.16.4",
+    "@testing-library/react": "^13.3.0",
+    "@testing-library/user-event": "^14.2.1",
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0",
+    "react-redux": "^8.0.2",
+    "react-scripts": "5.0.1",
+    "web-vitals": "^2.1.4"
   },
   "scripts": {
     "start": "react-scripts start",
     "build": "react-scripts build",
-    "eject": "react-scripts eject",
-    "test": "react-scripts test --env=node"
+    "test": "react-scripts test",
+    "eject": "react-scripts eject"
+  },
+  "eslintConfig": {
+    "extends": [
+      "react-app",
+      "react-app/jest"
+    ]
   },
-  "browserslist": [
-    ">0.2%",
-    "not dead",
-    "not ie <= 11",
-    "not op_mini all"
-  ]
+  "browserslist": {
+    "production": [
+      ">0.2%",
+      "not dead",
+      "not op_mini all"
+    ],
+    "development": [
+      "last 1 chrome version",
+      "last 1 firefox version",
+      "last 1 safari version"
+    ]
+  }
 }

examples/counter/package.json

@@ -1,11 +1,33 @@
-<!doctype html>
+<!DOCTYPE html>
 <html lang="en">
   <head>
-    <meta charset="utf-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1">
-    <title>Redux Counter Example</title>
+    <meta charset="utf-8" />
+    <link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <meta name="theme-color" content="#000000" />
+    <meta
+      name="description"
+      content="Web site created using create-react-app"
+    />
+    <link rel="apple-touch-icon" href="%PUBLIC_URL%/logo192.png" />
+    <!--
+      manifest.json provides metadata used when your web app is installed on a
+      user's mobile device or desktop. See https://developers.google.com/web/fundamentals/web-app-manifest/
+    -->
+    <link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
+    <!--
+      Notice the use of %PUBLIC_URL% in the tags above.
+      It will be replaced with the URL of the `public` folder during the build.
+      Only files inside the `public` folder can be referenced from the HTML.
+
+      Unlike "/favicon.ico" or "favicon.ico", "%PUBLIC_URL%/favicon.ico" will
+      work correctly both with client-side routing and a non-root public URL.
+      Learn how to configure a non-root public URL by running `npm run build`.
+    -->
+    <title>React Redux App</title>
   </head>
   <body>
+    <noscript>You need to enable JavaScript to run this app.</noscript>
     <div id="root"></div>
     <!--
       This HTML file is a template.
@@ -14,8 +36,8 @@
       You can add webfonts, meta tags, or analytics to this file.
       The build step will place the bundled scripts into the <body> tag.
 
-      To begin the development, run `npm start` in this folder.
-      To create a production bundle, use `npm run build`.
+      To begin the development, run `npm start` or `yarn start`.
+      To create a production bundle, use `npm run build` or `yarn build`.
     -->
   </body>
 </html>

examples/counter/public/favicon.ico

@@ -0,0 +1,25 @@
+{
+  "short_name": "React App",
+  "name": "Create React App Sample",
+  "icons": [
+    {
+      "src": "favicon.ico",
+      "sizes": "64x64 32x32 24x24 16x16",
+      "type": "image/x-icon"
+    },
+    {
+      "src": "logo192.png",
+      "type": "image/png",
+      "sizes": "192x192"
+    },
+    {
+      "src": "logo512.png",
+      "type": "image/png",
+      "sizes": "512x512"
+    }
+  ],
+  "start_url": ".",
+  "display": "standalone",
+  "theme_color": "#000000",
+  "background_color": "#ffffff"
+}

examples/counter/public/index.html

@@ -0,0 +1,2 @@
+# https://www.robotstxt.org/robotstxt.html
+User-agent: *

examples/counter/public/logo192.png

@@ -0,0 +1,39 @@
+.App {
+  text-align: center;
+}
+
+.App-logo {
+  height: 40vmin;
+  pointer-events: none;
+}
+
+@media (prefers-reduced-motion: no-preference) {
+  .App-logo {
+    animation: App-logo-float infinite 3s ease-in-out;
+  }
+}
+
+.App-header {
+  min-height: 100vh;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  font-size: calc(10px + 2vmin);
+}
+
+.App-link {
+  color: rgb(112, 76, 182);
+}
+
+@keyframes App-logo-float {
+  0% {
+    transform: translateY(0);
+  }
+  50% {
+    transform: translateY(10px);
+  }
+  100% {
+    transform: translateY(0px);
+  }
+}

examples/counter/public/logo512.png

@@ -0,0 +1,58 @@
+import React from 'react';
+import logo from './logo.svg';
+import { Counter } from './features/counter/Counter';
+import './App.css';
+
+function App() {
+  return (
+    <div className="App">
+      <header className="App-header">
+        <img src={logo} className="App-logo" alt="logo" />
+        <Counter />
+        <p>
+          Edit <code>src/App.js</code> and save to reload.
+        </p>
+        <span>
+          <span>Learn </span>
+          <a
+            className="App-link"
+            href="https://reactjs.org/"
+            target="_blank"
+            rel="noopener noreferrer"
+          >
+            React
+          </a>
+          <span>, </span>
+          <a
+            className="App-link"
+            href="https://redux.js.org/"
+            target="_blank"
+            rel="noopener noreferrer"
+          >
+            Redux
+          </a>
+          <span>, </span>
+          <a
+            className="App-link"
+            href="https://redux-toolkit.js.org/"
+            target="_blank"
+            rel="noopener noreferrer"
+          >
+            Redux Toolkit
+          </a>
+          ,<span> and </span>
+          <a
+            className="App-link"
+            href="https://react-redux.js.org/"
+            target="_blank"
+            rel="noopener noreferrer"
+          >
+            React Redux
+          </a>
+        </span>
+      </header>
+    </div>
+  );
+}
+
+export default App;

examples/counter/public/manifest.json

@@ -0,0 +1,15 @@
+import React from 'react';
+import { render } from '@testing-library/react';
+import { Provider } from 'react-redux';
+import { store } from './app/store';
+import App from './App';
+
+test('renders learn react link', () => {
+  const { getByText } = render(
+    <Provider store={store}>
+      <App />
+    </Provider>
+  );
+
+  expect(getByText(/learn/i)).toBeInTheDocument();
+});

examples/counter/public/robots.txt

@@ -0,0 +1,8 @@
+import { configureStore } from '@reduxjs/toolkit';
+import counterReducer from '../features/counter/counterSlice';
+
+export const store = configureStore({
+  reducer: {
+    counter: counterReducer,
+  },
+});

examples/counter/src/App.css

@@ -0,0 +1,67 @@
+import React, { useState } from 'react';
+import { useSelector, useDispatch } from 'react-redux';
+import {
+  decrement,
+  increment,
+  incrementByAmount,
+  incrementAsync,
+  incrementIfOdd,
+  selectCount,
+} from './counterSlice';
+import styles from './Counter.module.css';
+
+export function Counter() {
+  const count = useSelector(selectCount);
+  const dispatch = useDispatch();
+  const [incrementAmount, setIncrementAmount] = useState('2');
+
+  const incrementValue = Number(incrementAmount) || 0;
+
+  return (
+    <div>
+      <div className={styles.row}>
+        <button
+          className={styles.button}
+          aria-label="Decrement value"
+          onClick={() => dispatch(decrement())}
+        >
+          -
+        </button>
+        <span className={styles.value}>{count}</span>
+        <button
+          className={styles.button}
+          aria-label="Increment value"
+          onClick={() => dispatch(increment())}
+        >
+          +
+        </button>
+      </div>
+      <div className={styles.row}>
+        <input
+          className={styles.textbox}
+          aria-label="Set increment amount"
+          value={incrementAmount}
+          onChange={(e) => setIncrementAmount(e.target.value)}
+        />
+        <button
+          className={styles.button}
+          onClick={() => dispatch(incrementByAmount(incrementValue))}
+        >
+          Add Amount
+        </button>
+        <button
+          className={styles.asyncButton}
+          onClick={() => dispatch(incrementAsync(incrementValue))}
+        >
+          Add Async
+        </button>
+        <button
+          className={styles.button}
+          onClick={() => dispatch(incrementIfOdd(incrementValue))}
+        >
+          Add If Odd
+        </button>
+      </div>
+    </div>
+  );
+}

examples/counter/src/App.js

@@ -0,0 +1,78 @@
+.row {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+
+.row > button {
+  margin-left: 4px;
+  margin-right: 8px;
+}
+.row:not(:last-child) {
+  margin-bottom: 16px;
+}
+
+.value {
+  font-size: 78px;
+  padding-left: 16px;
+  padding-right: 16px;
+  margin-top: 2px;
+  font-family: 'Courier New', Courier, monospace;
+}
+
+.button {
+  appearance: none;
+  background: none;
+  font-size: 32px;
+  padding-left: 12px;
+  padding-right: 12px;
+  outline: none;
+  border: 2px solid transparent;
+  color: rgb(112, 76, 182);
+  padding-bottom: 4px;
+  cursor: pointer;
+  background-color: rgba(112, 76, 182, 0.1);
+  border-radius: 2px;
+  transition: all 0.15s;
+}
+
+.textbox {
+  font-size: 32px;
+  padding: 2px;
+  width: 64px;
+  text-align: center;
+  margin-right: 4px;
+}
+
+.button:hover,
+.button:focus {
+  border: 2px solid rgba(112, 76, 182, 0.4);
+}
+
+.button:active {
+  background-color: rgba(112, 76, 182, 0.2);
+}
+
+.asyncButton {
+  composes: button;
+  position: relative;
+}
+
+.asyncButton:after {
+  content: '';
+  background-color: rgba(112, 76, 182, 0.15);
+  display: block;
+  position: absolute;
+  width: 100%;
+  height: 100%;
+  left: 0;
+  top: 0;
+  opacity: 0;
+  transition: width 1s linear, opacity 0.5s ease 1s;
+}
+
+.asyncButton:active:after {
+  width: 0%;
+  opacity: 1;
+  transition: 0s;
+}

examples/counter/src/App.test.js

@@ -0,0 +1,6 @@
+// A mock function to mimic making an async request for data
+export function fetchCount(amount = 1) {
+  return new Promise((resolve) =>
+    setTimeout(() => resolve({ data: amount }), 500)
+  );
+}

examples/counter/src/app/store.js

@@ -0,0 +1,73 @@
+import { createAsyncThunk, createSlice } from '@reduxjs/toolkit';
+import { fetchCount } from './counterAPI';
+
+const initialState = {
+  value: 0,
+  status: 'idle',
+};
+
+// The function below is called a thunk and allows us to perform async logic. It
+// can be dispatched like a regular action: `dispatch(incrementAsync(10))`. This
+// will call the thunk with the `dispatch` function as the first argument. Async
+// code can then be executed and other actions can be dispatched. Thunks are
+// typically used to make async requests.
+export const incrementAsync = createAsyncThunk(
+  'counter/fetchCount',
+  async (amount) => {
+    const response = await fetchCount(amount);
+    // The value we return becomes the `fulfilled` action payload
+    return response.data;
+  }
+);
+
+export const counterSlice = createSlice({
+  name: 'counter',
+  initialState,
+  // The `reducers` field lets us define reducers and generate associated actions
+  reducers: {
+    increment: (state) => {
+      // Redux Toolkit allows us to write "mutating" logic in reducers. It
+      // doesn't actually mutate the state because it uses the Immer library,
+      // which detects changes to a "draft state" and produces a brand new
+      // immutable state based off those changes
+      state.value += 1;
+    },
+    decrement: (state) => {
+      state.value -= 1;
+    },
+    // Use the PayloadAction type to declare the contents of `action.payload`
+    incrementByAmount: (state, action) => {
+      state.value += action.payload;
+    },
+  },
+  // The `extraReducers` field lets the slice handle actions defined elsewhere,
+  // including actions generated by createAsyncThunk or in other slices.
+  extraReducers: (builder) => {
+    builder
+      .addCase(incrementAsync.pending, (state) => {
+        state.status = 'loading';
+      })
+      .addCase(incrementAsync.fulfilled, (state, action) => {
+        state.status = 'idle';
+        state.value += action.payload;
+      });
+  },
+});
+
+export const { increment, decrement, incrementByAmount } = counterSlice.actions;
+
+// The function below is called a selector and allows us to select a value from
+// the state. Selectors can also be defined inline where they're used instead of
+// in the slice file. For example: `useSelector((state: RootState) => state.counter.value)`
+export const selectCount = (state) => state.counter.value;
+
+// We can also write thunks by hand, which may contain both sync and async logic.
+// Here's an example of conditionally dispatching actions based on current state.
+export const incrementIfOdd = (amount) => (dispatch, getState) => {
+  const currentValue = selectCount(getState());
+  if (currentValue % 2 === 1) {
+    dispatch(incrementByAmount(amount));
+  }
+};
+
+export default counterSlice.reducer;

examples/counter/src/components/Counter.js

@@ -0,0 +1,33 @@
+import counterReducer, {
+  increment,
+  decrement,
+  incrementByAmount,
+} from './counterSlice';
+
+describe('counter reducer', () => {
+  const initialState = {
+    value: 3,
+    status: 'idle',
+  };
+  it('should handle initial state', () => {
+    expect(counterReducer(undefined, { type: 'unknown' })).toEqual({
+      value: 0,
+      status: 'idle',
+    });
+  });
+
+  it('should handle increment', () => {
+    const actual = counterReducer(initialState, increment());
+    expect(actual.value).toEqual(4);
+  });
+
+  it('should handle decrement', () => {
+    const actual = counterReducer(initialState, decrement());
+    expect(actual.value).toEqual(2);
+  });
+
+  it('should handle incrementByAmount', () => {
+    const actual = counterReducer(initialState, incrementByAmount(2));
+    expect(actual.value).toEqual(5);
+  });
+});

examples/counter/src/components/Counter.spec.js

@@ -0,0 +1,13 @@
+body {
+  margin: 0;
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
+    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
+    sans-serif;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+}
+
+code {
+  font-family: source-code-pro, Menlo, Monaco, Consolas, 'Courier New',
+    monospace;
+}

examples/counter/src/features/counter/Counter.js

@@ -1,20 +1,23 @@
-import React from 'react'
-import ReactDOM from 'react-dom'
-import { createStore } from 'redux'
-import Counter from './components/Counter'
-import counter from './reducers'
+import React from 'react';
+import { createRoot } from 'react-dom/client';
+import { Provider } from 'react-redux';
+import { store } from './app/store';
+import App from './App';
+import reportWebVitals from './reportWebVitals';
+import './index.css';
 
-const store = createStore(counter)
-const rootEl = document.getElementById('root')
+const container = document.getElementById('root');
+const root = createRoot(container);
 
-const render = () => ReactDOM.render(
-  <Counter
-    value={store.getState()}
-    onIncrement={() => store.dispatch({ type: 'INCREMENT' })}
-    onDecrement={() => store.dispatch({ type: 'DECREMENT' })}
-  />,
-  rootEl
-)
+root.render(
+  <React.StrictMode>
+    <Provider store={store}>
+      <App />
+    </Provider>
+  </React.StrictMode>
+);
 
-render()
-store.subscribe(render)
+// If you want to start measuring performance in your app, pass a function
+// to log results (for example: reportWebVitals(console.log))
+// or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals
+reportWebVitals();

examples/counter/src/features/counter/Counter.module.css

@@ -0,0 +1,13 @@
+const reportWebVitals = onPerfEntry => {
+  if (onPerfEntry && onPerfEntry instanceof Function) {
+    import('web-vitals').then(({ getCLS, getFID, getFCP, getLCP, getTTFB }) => {
+      getCLS(onPerfEntry);
+      getFID(onPerfEntry);
+      getFCP(onPerfEntry);
+      getLCP(onPerfEntry);
+      getTTFB(onPerfEntry);
+    });
+  }
+};
+
+export default reportWebVitals;

examples/counter/src/features/counter/counterAPI.js

@@ -1,4 +1,5 @@
-import { configure } from 'enzyme'
-import Adapter from 'enzyme-adapter-react-16'
-
-configure({ adapter: new Adapter() })
+// jest-dom adds custom jest matchers for asserting on DOM nodes.
+// allows you to do things like:
+// expect(element).toHaveTextContent(/react/i)
+// learn more: https://github.com/testing-library/jest-dom
+import '@testing-library/jest-dom/extend-expect';