Mini Diceroller

NPM Registry

Demo Site

A mini language written using ts-parsec to evaluate a string of rolled dice with arithmetic expressions.

Supported Syntax

| Syntax | Description | Example | |--------|-------------|---------| | NdS | Roll N S-sided dice | 2d6 | | dS | Roll a single S-sided die | d20 | | ^dS | Roll with advantage (2 dice, take highest) | ^d20 | | vdS | Roll with disadvantage (2 dice, take lowest) | vd20 | | + - | Addition / Subtraction | 1d20 + 5 - 2 | | * / | Multiplication / Division | 1d20 / 2 | | ( ) | Grouping | (1d6 + 2) * 3 | | -expr | Unary negation | -1d6, -(1d6 + 5) |

npm Commands

• npm run test - Runs test suite
• npm run build - Compiles TypeScript and outputs to dist/

API

import { exec, cmdEvaluate, parse, evaluate } from "mini-diceroller";

// Parse + evaluate, returns EvaluatedExpression
const result = exec("2d6 + 3");
result.v;          // total rolled value
result.stats.min;  // minimum possible value
result.stats.max;  // maximum possible value
result.stats.avg;  // average expected value

// Parse + evaluate, returns a formatted string
cmdEvaluate("2d6 + 3");
// => '[4, 2] + 3 > 9 {min: 5, max: 15, avg: 10 }'

// Lower-level: parse only, returns an Expression tree
const expr = parse("2d6 + 3");

Local REPL

[mini-diceroller]$ node
> const cmd = await import("./dist/index.js")
> cmd.cmdEvaluate("1d20 + 2")
'[13] + 2 > 15 {min: 3, max: 22, avg: 12.5 }'