PokéRoll
A CS2-style case opening simulator that rolls Pokémon from Gen 1–9. Plain HTML + CSS + JavaScript, no backend required.
Features
- Pick any mix of generations (Gen 1–9) and the Special group, view the case contents and the drop rate of each Pokémon
- 5 rarity tiers using CS2 odds: Blue 79.92% · Purple 15.98% · Pink 3.2% · Red 0.64% · Gold 0.26%, Shiny 1/100. A tier with no Pokémon in your selection drops to the next lower tier, and the odds table shows the real odds after that (e.g. "base 3.20% + 0.64% from Red")
- 6-second spinning card strip with tick sounds, a result sound, and a Quick open button
- Result popup with the exact odds of the drop (1 in N), and roll history
- Collection tab: search by name, Pokédex number or type; filter by generation, rarity or owned/missing/duplicates/shiny; sort by Pokédex number, rarity or copies; progress per generation and per rarity
- Custom tab, with its own generation selection:
- Type Roulette: spin a wheel for a type, then open cases of only that type
- Biome Roulette: spin a wheel for a Cobbleverse biome group, then open cases of Pokémon that spawn there
- Letter Roulette: spin a wheel for a letter from A to Z, then open cases of Pokémon whose name starts with it. Always uses every generation, Special forms included (under their original name)
- View case contents for the picked type or biome, or preview any other one, with each Pokémon's real odds and whether you own it
- Custom pool: in View case contents, pick which Pokémon of your type or biome case can drop (at least 6, with at least one Blue, Purple or Pink). Saved per type / biome and applied whenever the wheel lands on it again
- Minigame Case: just-for-fun cases with no rarity tiers and no Shiny, where every item has the same chance (1 in N). Pick a case, open it with the same reel, Quick open and Space key:
- Pokémon Case: every Pokémon (1025 + Special), always all generations. Drops are not added to your collection and don't change any stats
- Mega Stone Case: 156 Mega Stones from the Cobblemon mods Mega Showdown, ZA Mega and Mushiromega, with each stone's item image from its mod (shown pixel-sharp), the Mega form's type, stats, ability and crafting recipe. Stones go into their own Mega Stones collection on the Collection tab (filter by mod, search by stone or Pokémon name, duplicates counted)
- Minigame opens show in Recent drops and Roll history with a "Minigame" tag. They are saved in their own history (last 200), so they never push out your Case and Roulette opens
- Spawn locations for each Pokémon in the Cobbleverse modpack
- Special group: the 8 Kazeran forms from the Cobblemon addon Kazeran Eeveelutions, with their evolution methods. Ranked by the same BST rules, tracked separately in the collection (X/8)
- Animated odds table, page and popup transitions. Turned off when your system asks for reduced motion, or by opening
index.html?nomotion
Project structure
index.html the page; lists every stylesheet and script in load order
src/js/core/ configuration and timings, rolling and odds logic, Pokémon catalog, storage, shared state
src/js/ui/ parts used across pages: gen grid, odds table, reel, transition fallback timer,
popups, recent drops, sound, images, motion
src/js/pages/ the Case, Collection and Custom pages, and switching between them
src/js/modes/ Custom modes: shared wheel code and custom pool editor, then one file per mode
(type-roulette.js, biome-roulette.js, letter-roulette.js, minigame.js), then one file
per Minigame case (minigame-pokemon.js, minigame-megastones.js)
src/js/boot/ desktop footer and app start-up
src/css/ fonts.css, plus base/, layout/, components/, popups/, pages/ and modes/ styles;
each file also holds its own phone, tablet and reduced-motion rules
data/ generated data files (Pokémon, spawns, Special group, Mega Stones)
assets/ bundled images and fonts
electron/ desktop app: main process and preload
scripts/ data generators and the release script; scripts/data/ holds the Mega Stone CSV
tests/ logic tests (Node) and UI tests (Electron)
build/ icons used when packaging the desktop app
The site has no build step and uses plain <script> tags so it also runs from file://. Scripts load folder by folder: core → ui → pages → modes → boot. When you add a JS or CSS file, add its tag to index.html in the right position: a script must come after any file its top-level code depends on (code inside functions runs later and can use any file), stylesheets apply in the order they are listed, and src/js/boot/init.js stays last. The tests read the file list from index.html, so a file without a tag is not tested either.
Installing
Download the latest version from the Releases page:
- Windows:
PokeRoll-Setup-x.y.z.exe. The installer lets you choose the install folder and adds Desktop and Start Menu shortcuts; uninstall from Settings → Apps.
- Linux:
PokeRoll-x.y.z-linux-x86_64.AppImage. Make it executable (chmod +x) and run it.
The app isn't code-signed, so Windows SmartScreen may warn the first time: click More info → Run anyway.
After that the app updates itself. A few seconds after it starts, it checks for a new version and asks before downloading and before restarting to install. You can also click Check for updates at the bottom of the page. Your collection and roll history are kept across updates (and even if you uninstall).
Running
In the browser: double-click index.html.
Desktop app (Electron) — requires the LTS version of Node.js:
npm install
npm start # run in development (no update checks)
npm run dist # build the Windows installer → dist/
npm run dist:linux # build the Linux AppImage → dist/
Releasing
Every push to main and every pull request runs the tests on GitHub Actions (CI workflow), split into 4 shards that run in parallel. CI is green only when every shard passes. Nothing is built or published.
To publish a new version:
- Push your changes to
main and wait for CI to pass on that commit (CI runs).
- Run one of:
npm run release -- patch # 1.1.0 → 1.1.1 (fixes)
npm run release -- minor # 1.1.0 → 1.2.0 (new features)
npm run release -- major # 1.1.0 → 2.0.0
The script only goes ahead when everything is committed, main matches GitHub, CI has passed on that exact commit, and the new version is higher than every existing tag (a version is never reused). If CI is still running or has failed, it stops without creating a tag, so a red build never costs a version number. Checking CI uses GitHub's public API and needs no login.
It then bumps the version in package.json, commits, tags vX.Y.Z and pushes. The tag starts the Release workflow: it waits for CI on that exact commit to pass (it doesn't run the tests again, and stops without building if CI fails or never ran), builds the Windows installer and the Linux AppImage, and publishes them as a GitHub Release together with latest.yml and latest-linux.yml, which the installed apps read to find updates. If anything fails, nothing is published. Progress: Actions tab.
Testing
Requires npm install (the UI tests run the app in a hidden Electron window).
npm test # run every test suite
npm test -- roulette # only suites whose name contains "roulette"
npm test -- -v # print every check, not just failures
npm test -- --shard 2/4 # only shard 2 of 4 (what each CI job runs); add --list to just print its suites
tests/logic/ checks the rolling logic and odds in Node; tests/ui/ drives the app in Electron. Test data and screenshots go to a temporary folder (pokeroll-tests in the system temp directory), never to your own save data.
New suites go in the list in tests/suites.js. CI splits that list into 4 shards of about the same run time, using the times recorded there; a suite with no recorded time still runs (it is counted at the average time). The Release workflow doesn't run the tests again: it waits for CI on the release commit (see Releasing).
Updating data
node scripts/build-data.js # data/data.js — Pokémon info from PokeAPI
node scripts/build-spawns.js # data/spawns.js — spawn locations from the Cobbleverse Wiki
node scripts/build-images.js # assets/images/ — Pokémon images bundled with the app (works offline)
node scripts/build-special.js # data/special.js + assets/images/special/ — Special group, read from the mod file in special-src/
node scripts/build-megastones.js # data/megastones.js — Mega Stones, read from scripts/data/mega-stones.csv
node scripts/build-megastone-images.js # assets/images/megastones/ — Mega Stone item images, read from the mod files in megastone-src/
build-megastone-images.js needs the three mod files (mega_showdown-*.jar, zamega-*.jar, mushiromega-*.jar) in megastone-src/. That folder is not committed. The script finds each stone's image from the mod's own data, not by guessing the image name: the Mega definition whose showdown_id is the stone id (its file name is the item id), then that item's model, then the texture the model points to, copies the original 16×16 PNG unchanged, and stops without writing anything if any stone has no image.
build-special.js needs the mod file (e.g. Kazeran_Eeveelutions_v1.6.1.zip, downloaded from Modrinth) in special-src/. That folder is not committed.
Data sources
- PokeAPI — Pokémon info and images
- Cobbleverse Wiki — spawn locations in Cobbleverse
- Kazeran Eeveelutions — types, base stats, evolution methods and images of the Special group
- Mega Showdown, ZA Mega and Mushiromega (Cobblemon mods) — names, types, stats, abilities, recipes and item images of the Mega Stones
Credits
Kazeran Eeveelutions by Kazerio (https://modrinth.com/datapack/kazeran-eeveelutions), licensed CC-BY-NC-4.0.
The Kazeran forms (designs, names and images) belong to their original author, Kazerio. They are included here for non-commercial use only, under the terms of the CC-BY-NC-4.0 license.
Mega Stone data and images from the Cobblemon mods Mega Showdown and ZA Mega (YajatKaul, Navas) and Mushiromega. The stone images (assets/images/megastones/) are the mods' original item textures, copied unchanged. They belong to the mods' authors and are included here for non-commercial use only.
Disclaimer
PokéRoll is a non-commercial fan project and is not affiliated with Nintendo, Game Freak or The Pokémon Company.
Pokémon and Pokémon character names are trademarks of © Nintendo / Creatures Inc. / GAME FREAK inc.
Data: PokeAPI · Cobbleverse Wiki · Mega Stone data and images: Mega Showdown and ZA Mega (YajatKaul, Navas), Mushiromega, non-commercial use only — Created by Bubi
