Single-player sports simulation games. Make trades, set rosters, draft players, and try to build the next dynasty, all from within your web browser. The games are implemented entirely in client-side JavaScript, backed by IndexedDB.
Copyright (C) ZenGM, LLC. All rights reserved.
Email: jeremy@zengm.com
Website: https://zengm.com/
Development: https://github.com/zengm-games/zengm
Discussion:
- https://www.reddit.com/r/BasketballGM/
- https://www.reddit.com/r/Football_GM/
- https://www.reddit.com/r/ZenGMBaseball/
- https://www.reddit.com/r/ZenGMHockey/
- https://zengm.com/discord/
This project is NOT open source, but it is also not completely closed. Please see LICENSE.md for details.
If you just want to play the game, go to https://zengm.com/. Instructions below are for developers who want to run a copy locally so they can make changes to the code.
If you want to contribute but get stuck somewhere, please contact me! I'm happy to help.
This project is NOT open source, but it is also not completely closed. Please see LICENSE.md for details.
If you want to contribute code to this project, you must sign a contributor license agreement. There are separate forms for individuals and entities (such as corporations):
- Individual CLA (this is probably what you want)
- Entity CLA
Make a copy of the form, fill in your information at the bottom, and send an email to jeremy@zengm.com with the subject line, "Contributor License Agreement from YOUR_NAME_HERE (GITHUB_USERNAME_HERE)".
Make sure you're using a recent version of Node.js, older versions probably won't work. Then, all of the tooling used in development can be set up by simply installing pnpm and running:
pnpm install
from within this folder.
To build the app along with all its assets, run
pnpm run build
However during development, you probably would rather do
pnpm run start-watch
which will start the server and watch JS and CSS files for changes and
recompile. This simply runs both pnpm run start and pnpm run watch together,
which alternatively can be run separately if you wish.
By default this will build the basketball version of the game. For other sports, set the SPORT environment variable to "football", "baseball", or "hockey", like:
SPORT=football pnpm run start-watch
Open package.json to see all available development scripts.
To run the game locally, you need some way of running a web server to display the content. There are currently two ways to do it. It doesn't matter which you use as long as you can get it to run on your computer.
Run
pnpm run start
and point your browser to http://localhost:3000/ (or it will use a different
port if 3000 is already used by somethign else). If you use the command pnpm run start-watch from above, then running the command pnpm run start is not
necessary.
The mod_rewrite rules in .htaccess let the game run in Apache. Everything
should work if you point it at the build folder with mod_rewrite enabled.
TypeScript and ESLint are used to enforce some coding standards. To run them on the entire codebase, run
pnpm run lint
Integration and unit tests spread out through the codebase in *.test.ts files. Coverage is not great. They can be run from the command line with
pnpm test
There is also a single end-to-end test which creates a league and simulates a season. To execute the end-to-end test, run
pnpm run test-e2e
For the end-to-end test, by default it is basketball. If you want it to do
football, stick SPORT=football in front.
This is a single-page app that runs almost entirely client-side by storing data
in IndexedDB. The core of the game runs inside a Shared Worker (or a Web Worker
in crappy browsers that don't support Shared Workers), and then each open tab
runs only UI code that talks to the worker. The UI code is in the src/ui
folder and the core game code is in the src/worker folder. They communicate
through the toUI and toWorker functions.
The UI is built with React and Bootstrap.
In the worker, data is ultimately stored in IndexedDB, but for performance and
cross-browser compatibility reasons, a cache (implemented in
src/worker/db/Cache.ts) sits on top of the database containing all commonly
accessed data. The idea is that IndexedDB should only be accessed for uncommon
situations, like viewing stats from past seasons. For simulating games and
viewing current data, only the cache should be necessary.
The cache is overly complicated because (1) the values it returns are mutable,
so you better not mess with them accidentally, and (2) when you do purposely
mutate a value (like updating a player's stats), you need to remember to always
write it back to the cache manually by calling idb.cache.*.put.
In both the worker and UI processes, there is a global variable self.bbgm
which gives you access to many of the internal functions of the game from
within your browser.
As mentioned above, the core of a game runs in a Shared Worker. This makes
debugging a little tricky. For instance, in Chrome, if you console.log
something inside the Shared Worker, you won't see it in the normal JS console.
Instead, you need to go to chrome://inspect/#workers and click "Inspect" under
http://localhost/gen/worker.js.
In any browser, if you have two tabs open and you reload one of them, the worker process will not reload. So make sure you close all tabs except one before reloading if you want to see changes in the worker.
This only applies if you use Apache, not if you use pnpm run start!
A service worker is used for offline caching. This can make development tricky, because if you load the game in your browser, make a change, wait for build/watch to finish, and then reload... you will not see your change because it will cache the original version and then not update it on a reload. This is the normal behavior for service workers (they only switch to a new version when you actually close the website and reopen it, not on a reload), but it makes development annoying.
To work around that, in Chrome you can use the "Update on reload" option and keep your devtools open. Then reloading will always get you the latest version.
Even with that, ctrl+shift+r may be a good idea to make sure you're seeing your latest changes.
If you want to contribute changes back to the project, first create a fork on GitHub. Then make your changes in a new branch. Confirm that the tests (hopefully including new ones you wrote!) and ESLint all pass. Finally, send me a pull request.
It's also probably a good idea to create an issue on GitHub before you start working on something to keep me in the loop.
Abbreviations of stats should be done like basketball-reference.com and football-reference.com stat pages. For instance, "defensive rebounds" is "drb".
Shout out to BrowserStack for helping with cross-browser testing.