Nick/useState

README.md

@@ -1,6 +1,6 @@
 # Minesweeper
 
-## Section 1: Introduction
+## Section: Introduction
 
 ### Minesweeper presentation
 
@@ -19,7 +19,7 @@
 
 [Pull request](https://github.com/nickovchinnikov/minesweeper/pull/2)
 
-## Section 2: Typescript recap
+## Section: Typescript recap
 
 ### Typescript basic
 ### Parametric typing with generics
@@ -35,7 +35,7 @@
 
 [Pull request](https://github.com/nickovchinnikov/minesweeper/pull/4)
 
-## Section 3: React intro
+## Section: React intro
 
 ### Create React App
 
@@ -64,7 +64,7 @@
 
 [React intro examples pull request](https://github.com/nickovchinnikov/minesweeper/pull/10/files)
 
-## Section 4: Jest, TDD and basic game logic
+## Section: Jest, TDD and basic game logic
 
 ### Jest testing framework (TDD vs TLD)
 
@@ -85,7 +85,7 @@
 
 [config for vscode](https://gist.github.com/nickovchinnikov/ace62c117e6b6ff87f0fbfe96bb04164)
 
-## Section 5: Storybook and Components Library
+## Section: Storybook and Components Library
 
 ### Library Emotion for css-in-js
 
@@ -115,10 +115,12 @@
 
 [Pull request](https://github.com/nickovchinnikov/minesweeper/pull/14)
 
-## Section 6: React Hooks intro
+## Section: React Hooks intro
 
 ### useState
 
+[Pull request](https://github.com/nickovchinnikov/minesweeper/pull/41)
+
 ### Dynamic components with useState Hook
 
 [Pull request](https://github.com/nickovchinnikov/minesweeper/pull/15)
@@ -153,7 +155,7 @@
 
 [Pull request](https://github.com/nickovchinnikov/minesweeper/pull/38)
 
-## Section 7: Code quality, app deploy and CI/CD
+## Section: Code quality, app deploy and CI/CD
 
 ### Test coverage report
 ### Test quality tool Stryker-Mutator
@@ -175,7 +177,7 @@
 
 [Pull request3](https://github.com/nickovchinnikov/minesweeper/pull/23)
 
-## Section 8: React hooks and react testing library
+## Section: React hooks and react testing library
 
 ### Static game
 
@@ -203,7 +205,7 @@
 
 [Pull request](https://github.com/nickovchinnikov/minesweeper/pull/28/files)
 
-## Section 9: Game Hook
+## Section: Game Hook
 
 ### Create game over behavior by TDD
 
@@ -217,7 +219,7 @@
 
 [Pull request](https://github.com/nickovchinnikov/minesweeper/pull/31/files)
 
-## Section 9: Game behavior and useEffect
+## Section: Game behavior and useEffect
 
 ### Set flag action
 
@@ -229,7 +231,7 @@
 
 [Pull request](https://github.com/nickovchinnikov/minesweeper/pull/33/files)
 
-## Section 10: useEffect and useCallback
+## Section: useEffect and useCallback
 
 ### Game timer and useEffect
 

examples/useStateAndUseEffect/ClickCounter.test.tsx

@@ -0,0 +1,28 @@
+import React from 'react';
+import { render, screen, fireEvent } from '@testing-library/react';
+
+import { ClickCounter } from './ClickCounter';
+
+describe('Test ClickCounter', () => {
+  it('should inc/dec counter when buttons inc/dec clicked', () => {
+    render(<ClickCounter />);
+
+    const counter = screen.getByRole('heading');
+    const increaseBtn = screen.getByRole('button', { name: 'Increase' });
+    const decreaseBtn = screen.getByRole('button', { name: 'Decrease' });
+
+    expect(counter.textContent).toBe('Counter: 0');
+
+    fireEvent.click(increaseBtn);
+    expect(counter.textContent).toBe('Counter: 1');
+
+    fireEvent.click(increaseBtn);
+    expect(counter.textContent).toBe('Counter: 2');
+
+    fireEvent.click(decreaseBtn);
+    expect(counter.textContent).toBe('Counter: 1');
+
+    fireEvent.click(decreaseBtn);
+    expect(counter.textContent).toBe('Counter: 0');
+  });
+});

examples/useStateAndUseEffect/ClickCounter.tsx

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+import React, { FC, useState } from 'react';
+
+interface Props {
+  defaultCount?: number;
+}
+
+export const ClickCounter: FC<Props> = ({ defaultCount = 0 }) => {
+  const [count, setCount] = useState(defaultCount);
+
+  return (
+    <div>
+      <h1>Counter: {count}</h1>
+      <button onClick={() => setCount(count + 1)}>Increase</button>
+      <button onClick={() => setCount(count - 1)}>Decrease</button>
+    </div>
+  );
+};