Mayhem Tracker

A local Windows web app for tracking League of Legends matches through the League client's local API. The frontend runs in the browser, the Node.js backend stays local, and data is stored in SQLite on the machine.

Stack

• Frontend: React 19, TypeScript, Vite, Tailwind CSS v4, shadcn/ui
• Backend: Node.js, Express, TypeScript, league-connect
• Storage: SQLite with better-sqlite3
• Monorepo: pnpm workspaces

Prerequisites

• Windows
• Node.js
• pnpm
• League of Legends client installed

Installation

pnpm install

Run

In development:

pnpm dev

Ou via le script Windows fourni:

start-mayhemtracker.bat

This starts:

• the Vite frontend on http://localhost:5173
• the Express backend on http://localhost:3001

The Vite proxy automatically routes /api/* and /assets-cache/* to the local backend.

Useful scripts

pnpm dev
pnpm dev:client
pnpm dev:server
pnpm build
pnpm test
pnpm test:client
pnpm verify
pnpm db:reset

Frontend tests

Tests use Vitest + Testing Library on the client side.

pnpm test:client

The currently covered scenarios validate:

• resetting preferences in Settings
• opening a detail view from an interactive table
• expanding the history/detail flow

Local storage

By default, local data is written to:

%USERPROFILE%/.mayhemtracker

Main contents:

• db/mayhemtracker.sqlite: persistent SQLite database
• cache/icons/: disk cache for champion, item, and augment icons
• static-data/: sync files and Riot metadata

You can override this folder with the MAYHEMTRACKER_STORAGE_DIR environment variable.

Local backend endpoints

• GET /api/status
• GET /api/league/connection
• GET /api/league/auth
• GET /api/league/summoner
• GET /api/league/gameflow
• GET /api/system/powershell-test
• POST /api/static-data/sync
• GET /api/static-data/champions
• GET /api/static-data/augments
• GET /api/static-data/items
• POST /api/matches/sync-current
• GET /api/matches
• GET /api/matches/:matchId
• DELETE /api/matches/clear

Integration notes

• The application is designed for local-only usage.
• league-connect is only used on the backend side.
• The frontend only calls local HTTP routes under /api/....
• The backend also serves the local icon cache through /assets-cache/....
• If the League client is not open, League routes return a clean JSON error.