@randsum/dice
Advanced Dice Rolling for JavaScript & TypeScript
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A flexible, type-safe dice rolling implementation for tabletop RPGs, game development, and probability simulations that supports:
- ðē Standard dice notation (`4d6`, `2d20H`, etc.)
- ðŊ Complex modifiers (drop lowest, reroll, exploding dice)
- ð Full TypeScript support with intelligent type inference
- ðŪ Perfect for games, RPGs, and simulations
- ðŠķ Tree-shakeable implementation for minimal bundle size
- ðĶ Optimized for performance and reliability
- ð§Đ Extensible architecture for custom game systems
- ð Works in Node.js, browsers, and React Native
## Installation
```bash
npm install @randsum/dice
# or
yarn add @randsum/dice
# or
bun add @randsum/dice
```
## CLI Usage
Roll dice directly from your terminal:
```bash
npx randsum 2d20 # Roll two twenty-sided dice
npx randsum 4d6L # Roll 4d6, drop lowest
npx randsum 3d8+2 # Roll three d8s and add 2
```
Example output:
```text
ðē Roll Result:
âââââââââââââââ
Total: 24
Rolls: [14, 10]
Description: Roll 2d20
```
## Usage
```typescript
import { D, D20, D6, roll } from '@randsum/dice'
// Using premade dice
D20.roll() // Roll a d20
D6.roll(4) // Roll 4d6
// Create custom dice
const d12 = D(12)
d12.roll() // Returns number 1-12
d12.rollSpread(3) // Returns [n, n, n]
// Create dice with custom faces
const coin = D(['heads', 'tails'])
coin.roll() // Returns "heads" or "tails"
// Using the roll function
roll('4d6L') // 4d6, drop lowest
roll('2d20H') // 2d20, keep highest
roll('4d6R{<3}') // 4d6, reroll values below 3
```
## Available Dice
- `D4`, `D6`, `D8`, `D10`, `D12`, `D20`, `D100`: Standard numeric dice
- `Coin`: Two-sided die with 'heads' and 'tails'
- `FudgeDice`: Fate/Fudge dice with +, -, and blank faces
- `AlphaNumDie`: Custom die with alphanumeric faces
## API Reference
### `D` Class
```typescript
// Create numeric die
const d20 = D(20)
d20.roll() // Returns 1-20
// Create custom die
const colorDie = D(['red', 'blue', 'green'])
colorDie.roll() // Returns random color
```
### `roll` Function
```typescript
// Basic rolls
roll(20) // Roll 1d20
roll('4d6') // Roll 4d6
// Using RollOptions object
roll({
sides: 6,
quantity: 4,
modifiers: {
drop: { lowest: 1 }, // Drop lowest roll
plus: 2 // Add 2 to total
}
})
// Multiple dice in one roll
roll('2d20', '4d6', '1d8') // Roll them all at once
roll(D20, D6, D8) // Using predefined dice
roll(
{
sides: 20,
quantity: 2
},
{
sides: 6,
quantity: 4
}
) // Using options objects
// Mix and match different argument types
roll(
'2d20H', // Notation string, with modifiers
D6, // Die instance
{
// Options object
sides: 8,
quantity: 2,
modifiers: {
explode: true // Exploding dice
}
},
12 // Simple number (1d12)
)
// Different Result Types Examples:
// Numeric Results (type: 'numeric')
const numericResult = roll('4d6')
// {
// type: 'numeric',
// result: [3, 4, 5, 2],
// total: 14, // number
// ...
// }
// Custom Results (type: 'custom')
const customResult = roll(D(['critical', 'hit', 'miss']))
// {
// type: 'custom',
// result: ['critical'],
// total: 'critical', // string
// ...
// }
// Mixed Results (type: 'mixed')
const mixedResult = roll(
'2d6', // numeric dice
D(['hit', 'miss']) // custom dice
)
// {
// type: 'mixed',
// result: [4, 6, 'hit'],
// total: '10, hit', // string
// ...
// }
// Custom-faced dice
roll(D(['critical', 'hit', 'miss']))
roll({
sides: ['heads', 'tails'],
quantity: 3
})
// With modifiers
roll('4d6L') // Drop lowest
roll('2d20H') // Keep highest
roll('3d8!') // Exploding dice
roll('4d6R{<3}') // Reroll values below 3
```
See [Dice Notation Reference](https://github.com/RANDSUM/randsum/blob/main/packages/notation/RANDSUM_DICE_NOTATION.md) for all supported modifiers.
## Bundle Size Optimization
This package is optimized for minimal bundle size and supports tree-shaking. For the smallest possible bundles, import only what you need:
```typescript
// â Imports everything
import * as dice from '@randsum/dice'
// â
Only imports what you need
import { D20, roll } from '@randsum/dice'
// â
Best for tree-shaking - direct imports
import { D20 } from '@randsum/dice/premadeDice'
import { roll } from '@randsum/dice/roll'
```
## Use Cases
### Virtual Tabletop Applications
```typescript
import { roll } from '@randsum/dice'
// Handle player attack roll
function handleAttackRoll(characterLevel, strengthModifier, hasAdvantage) {
const notation = hasAdvantage ? '2d20H' : '1d20'
const attackRoll = roll(`${notation}+${strengthModifier}+${Math.floor(characterLevel / 2)}`)
return {
total: attackRoll.sum,
critical: attackRoll.rolls.includes(20),
fumble: attackRoll.rolls.includes(1)
}
}
```
### Game Development
```typescript
import { D6, D20 } from '@randsum/dice'
class LootTable {
generateLoot(playerLevel) {
const rarity = this.determineRarity(playerLevel)
return this.rollForItem(rarity)
}
private determineRarity(playerLevel) {
const roll = D20.roll()
if (roll >= 18 + Math.min(playerLevel, 10)) return 'legendary'
if (roll >= 15) return 'rare'
if (roll >= 10) return 'uncommon'
return 'common'
}
private rollForItem(rarity) {
// Implementation details...
}
}
```
### Probability Simulations
```typescript
import { roll } from '@randsum/dice'
// Simulate 10,000 character stat rolls
function simulateStatRolls(iterations = 10000) {
const results = []
for (let i = 0; i < iterations; i++) {
const stats = Array.from({ length: 6 }, () => roll('4d6L').sum)
results.push(stats)
}
// Calculate average stat value
const allStats = results.flat()
const average = allStats.reduce((sum, stat) => sum + stat, 0) / allStats.length
return {
average,
min: Math.min(...allStats),
max: Math.max(...allStats)
// Further analysis...
}
}
```
## Related Packages
- [@randsum/notation](https://github.com/RANDSUM/randsum/tree/main/packages/notation): Dice notation parser
- [@randsum/5e](https://github.com/RANDSUM/randsum/tree/main/gamePackages/5e): 5th Edition compatible dice rolling
- [@randsum/blades](https://github.com/RANDSUM/randsum/tree/main/gamePackages/blades): Blades in the Dark dice system
- [@randsum/daggerheart](https://github.com/RANDSUM/randsum/tree/main/gamePackages/daggerheart): Daggerheart dice system
- [@randsum/root-rpg](https://github.com/RANDSUM/randsum/tree/main/gamePackages/root-rpg): Root RPG dice system
- [@randsum/salvageunion](https://github.com/RANDSUM/randsum/tree/main/gamePackages/salvageunion): Salvage Union dice system