D&D Companion

A lightweight, modular Dungeons & Dragons companion app built with Tauri v2, Svelte, TypeScript, and Rust.

Architecture

The app is a black workspace where sub apps open as draggable internal windows. Sub apps communicate through a JSON event bus.

┌─────────────────────────────────────────┐
│  Toolbar  [Dice Roller] [Spell List]    │
├─────────────────────────────────────────┤
│                                         │
│   ┌─ Dice Roller ──┐  ┌─ Spell List ─┐ │
│   │                 │  │              │ │
│   │   [D20] → 17   │  │  Fire Bolt   │ │
│   │                 │  │  🎲 1D10 ──────── eventBus ──→ Dice Roller
│   │   History...    │  │              │ │
│   └─────────────────┘  └──────────────┘ │
│                                         │
└─────────────────────────────────────────┘

Event Bus

Sub apps send JSON messages to each other:

{ "target": "diceRoller", "source": "spellList", "action": "roll", "dice": "1D10" }

Response:

{ "target": "spellList", "source": "diceRoller", "action": "rollResult", "dice": "1D10", "result": 7 }

Adding a New Sub App

1. Create src/apps/yourApp/YourApp.svelte
2. Add entry to configs/registry.json
3. Subscribe to the event bus in onMount
4. Add the component route in App.svelte

Documentation

• JSON Reference & AI Prompts — full schema for every sub app, worked examples, and copy-paste AI prompts to generate character data

Setup

Prerequisites

• Node.js ≥ 18
• Rust (latest stable)
• Tauri v2 prerequisites: https://v2.tauri.app/start/prerequisites/

Install & Run

# Install JS dependencies
npm install

# Run in development mode (opens desktop window)
npm run tauri dev

# Build for production
npm run tauri build

Development (frontend only, no Tauri)

npm run dev
# Open http://localhost:1420

Folder Structure

src/
  main.ts                        # Entry point
  App.svelte                     # Workspace manager
  lib/
    types.ts                     # Shared TypeScript types
    eventBus.ts                  # JSON message bus
    appRegistry.ts               # Sub app registry
    dice.ts                      # Dice parsing & rolling engine
  apps/
    diceRoller/
      DiceRoller.svelte          # Dice Roller UI
    spellList/
      SpellList.svelte           # Spell List UI
    spellSlots/
      SpellSlots.svelte          # Spell Slot tracker
    spellcasting/
      Spellcasting.svelte        # Spellcasting stats
    magicItems/
      MagicItems.svelte          # Magic item inventory
    goldPurse/
      GoldPurse.svelte           # Currency tracker
    inventory/
      Inventory.svelte           # Equipment & items
    weaponsCantrips/
      WeaponsCantrips.svelte     # Weapons & cantrips
    hpTracker/
      HpTracker.svelte           # Hit point tracker
    skills/
      Skills.svelte              # Skill proficiencies
    traits/
      Traits.svelte              # Character traits
    proficiencies/
      Proficiencies.svelte       # Proficiency list
    notes/
      Notes.svelte               # Session notes
    characterProfile/
      CharacterProfile.svelte    # Character overview
  components/
    WindowFrame.svelte           # Draggable window wrapper
    Toolbar.svelte               # Top toolbar
    MobileNav.svelte             # Mobile navigation
    SettingsPanel.svelte         # App settings
src-tauri/
  src/
    lib.rs                       # Rust commands (dice, config I/O)
    main.rs                      # Desktop entry point
  tauri.conf.json                # Tauri config
configs/
  registry.json                  # Sub app registry
  diceRoller.json                # Dice Roller saved state
  spellList.json                 # Spell data

Sub Apps

Dice Roller

• Quick-pick: D2, D3, D4, D6, D8, D10, D12, D20, D100
• Custom input: 2D8+3, 1D20-1
• Roll history
• Listens on the bus for roll requests

Spell List

• Spell cards loaded from JSON
• Add / edit / delete spells
• Import / export spell JSON files
• Clickable damage dice → sends roll request to Dice Roller
• School-colored card accents
• Cantrip upgrade display for level 0 spells

Other Sub Apps

• HP Tracker — current / max HP with temp HP and death saves
• Spell Slots — track spell slot usage per level
• Spellcasting — spellcasting ability, save DC, and attack bonus
• Skills — skill list with proficiency toggles
• Weapons & Cantrips — attack actions with roll integration
• Inventory — general equipment list
• Magic Items — attunement-aware magic item tracker
• Gold Purse — multi-denomination currency tracker (GP/SP/CP)
• Traits — personality traits, ideals, bonds, flaws
• Proficiencies — armor, weapon, tool, and language proficiencies
• Notes — freeform session notes
• Character Profile — name, race, class, background, and stats