JS Slot Machine

JS Slot Machine is a Progressive web app with a regular slot machine game that has the logos of main JS-related tools as symbols. Deployed at https://marianapatcosta.github.io/js-slots-cra.

Implemented Functionalities

Game features

• Slot Machine with 5 reels (with > 30 symbols) and 3 rows, with 9 Pay lines.

• Follows the general rules of slot games, i.e, it aims to make the symbols spin and then check if you have combinations of 3 or more equal symbols displayed at one of the 9 possible winning lines;

• Different win factor according to symbol frequency and number of symbol matches (from 3 to 5);

• Customizable bet amount;

• AutoSpin capability;

• Free spinnings;

• Bonus WildCards;

• Big winning due to win amount multipliers;

• Special Symbols;

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• Sounds on button click, winning, loss and spinning;

• Lights blinking on winning and animation on matching symbols (including when Bonus wildcards are won);

General features

• Offline capability;
• Instalable in your device;
• Responsive design;
• Dark theme;
• Background theme;
• Multilanguage (English and Portuguese);
• Share game url;

Lighthouse report for Desktop

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Technical Stack

• TypeScript;
• React (use of functional components and hooks, portal, context, custom hooks);
• Redux (including persistence middleware to store state at localStorage);
• Webpack /CRA;
• SCSS modules with BEM methodology;
• typed-scss-modules (to generate TypeScript definitions for SCSS modules);
• HTML Canvas (for drawing Pay Lines);
• react-i18next for internationalization;
• CSS animations (for symbol SVGs and fake loader);
• Jest and React Testing library (for some unit tests with test coverage);
• react-transition-group (for modal/toast transitions);
• GreenSock Animation Platform (GSAP) (for spin animation);
• Basic ESlint and Prettier configs;
• GitHub actions
• Cypress (basic setup only);

What I've used but had to let go

Vite (repo and deploy )

• Error on running unit tests due to a supposed error with react-i18n and vite-plugin-pwa mocks;
• Tool to generate type definitions for scss (vite-plugin-sass-dts) caused errors;
• Problems when registering web workers;

Issues

Spin animation is buggy (after stop spinning, there is a 'jump' to show the win screen)

Attempts:

• no tool animation;
• GSAP animation of all symbols, of reel as a whole, both depending on isSpinning redux state;
• Add the final slot screen symbols at the end of spinning;
• Prepare the shuffled reels with final slot screen symbols before spinning (but reels do not stay at proper position, showing the wrong symbols for final slot screen);
• DOM manipulation with ids and determining the visible reels by assessing top css property (ugly code);
• useImperativeHandle hook to execute reel animation from parent component and overcome the state update issue was not working;

CRA

• no support for path alias (add craco to overcome this issue);
• Cypress configuration needs several additional packages and I could not run the first test I wrote because cypress/webpack-preprocessor (needed e.g. to load scss files) is incompatible with React v18.1.

Available Scripts

In the project directory, you can run:

yarn install

Installs all the dependencies required to run and develop this application.

yarn start

Runs the app in the development mode.
Open http://localhost:3000 to view it in the browser.

yarn build

Build a production-ready application.

yarn lint

Run linter command.

yarn validate-ts

Runs TypeScript validator

yarn gen-scss-types

Runs typed-scss-modules and generates types for scss modules, keeping the namespace using BEM css methodology

yarn test:unit

Launches the unit test runner in the interactive watch mode.

yarn test:unit-coverage

Launches the unit test runner in the interactive watch mode and shows test coverage report.

yarn test:e2e

Launches cypress tests.

yarn deploy

Deploy the build app to GitHub pages.