counter folder removed

minimal-app/src/features/counter/counter.js

-import { useSelector, useDispatch } from 'react-redux';
-import PropTypes from 'prop-types';
-
-import classNames from 'classnames';
-import styles from './counter.module.css';
-
-import {
-  selectValue,
-  setValue,
-} from './counterSlice.js';
-
-export function Counter(props) {
-  const value = useSelector(selectValue);
-  const dispatch = useDispatch();
-
-  const classes = classNames({
-    [styles.red]: value % 2 === 0,
-    [styles.blue]: value % 2 === 1,
-  });
-  const onClick = () => dispatch(setValue({
-    value: value + 1,
-  }));
-
-  return (
-    <label>
-      {props.label}:&nbsp;
-      <button className={classes} onClick={onClick}>
-        {value}
-      </button>
-    </label>
-  );
-}
-
-Counter.propTypes = {
-  label: PropTypes.string.isRequired,
-};

minimal-app/src/features/counter/counter.module.css

-.red {
-  color: rgba(255 0 0 / 100%);
-}
-
-.blue {
-  color: rgba(0 0 255 / 100%);
-}

minimal-app/src/features/counter/counter.test.js

-import { render, screen } from '@testing-library/react';
-import userEvent from '@testing-library/user-event';
-import '../../testing/mockRedux.js';
-
-import { Counter } from './counter.js';
-
-import {
-  selectValue,
-  setValue,
-} from './counterSlice.js';
-jest.mock('./counterSlice.js', () => ({
-  selectValue: jest.fn().mockName('selectValue'),
-  setValue: jest.fn().mockName('setValue'),
-}));
-
-describe('the button', () => {
-  test('displays the value from the store', () => {
-    selectValue.mockReturnValue(9999);
-    render(<Counter label={'Foo'} />);
-    expect(screen.getByRole('button')).toHaveTextContent(/^9999$/);
-  });
-  test('is red when the value from the store is even', () => {
-    selectValue.mockReturnValue(9998);
-    render(<Counter label={'Foo'} />);
-    expect(screen.getByRole('button')).toHaveClass('red');
-  });
-  test('is blue when the value from the store is odd', () => {
-    selectValue.mockReturnValue(9999);
-    render(<Counter label={'Foo'} />);
-    expect(screen.getByRole('button')).toHaveClass('blue');
-  });
-  test('increments the value in the store when clicked', async() => {
-    selectValue.mockReturnValue(9999);
-    render(<Counter label={'Foo'} />);
-    await userEvent.click(screen.getByRole('button'));
-    expect(setValue).toHaveBeenCalledTimes(1);
-    expect(setValue).toHaveBeenCalledWith({
-      value: 9999 + 1,
-    });
-  });
-});

minimal-app/src/features/counter/counterSlice.js

-import { createSlice } from '@reduxjs/toolkit';
-
-const counterSlice = createSlice({
-  name: 'counter',
-  initialState: {
-    value: 0,
-  },
-  reducers: {
-    setValue: (counter, action) => {
-      const {
-        value,
-      } = action.payload;
-      counter.value = value;
-    },
-  },
-});
-export default counterSlice;
-
-export const {
-  setValue,
-} = counterSlice.actions;
-
-export function selectValue(state) {
-  return state.counter.value;
-}

minimal-app/src/features/counter/counterSlice.test.js

-import counterSlice, {
-  selectValue,
-  setValue,
-} from './counterSlice.js';
-
-describe('the initial state', () => {
-  test('has a value of zero', () => {
-    const state = counterSlice.reducer(undefined, {});
-    expect(state).toEqual({
-      value: 0,
-    });
-  });
-});
-
-describe('selectValue', () => {
-  test('reads the stored value', () => {
-    const state = {
-      value: 9999,
-    };
-    const result = selectValue({ [counterSlice.name]: state });
-    expect(result).toBe(9999);
-  });
-});
-
-describe('setValue', () => {
-  test('overwrites the stored value', () => {
-    const state = counterSlice.reducer({
-      value: 8888,
-    }, setValue({
-      value: 9999,
-    }));
-    expect(state).toEqual({
-      value: 9999,
-    });
-  });
-});