node.js package for rolling dice and adding modifiers. ex: 2d6+1

Usage no npm install needed!

<script type="module">
  import roll from '';



Roll is a node.js package for rolling dice and adding modifiers (such as "2d6+1").


build status

How To Use (From Shell)

Installation (via npm)

$ npm install -g roll


$ roll 2d6+3
$ roll d20
$ roll d%
$ roll -d 2d20
Dice: 13, 8
Total: 21
$ roll --detail 5d%
Dice: 45, 86, 86, 4, 72
Total: 293

How To Use (As Library)

Installation (via npm)

$ npm install roll


Get an instance of the library:

var Roll = require('roll'),
  roll = new Roll();

Rolling a single die:

var oneDie = roll.roll('d6');
console.log(oneDie.result); //random number between 1 and 6 (inclusive)

Rolling multiple dice:

var twoTwenties = roll.roll('2d20');
console.log(twoTwenties.result); //random number between 2 and 40 (inclusive)

Rolling multiple sets of dice:

var bunchOfDice = roll.roll('2d20+1d12');
console.log(bunchOfDice.result); //random number between 3 and 52 (inclusive)

Rolling a percentage:

var chance = roll.roll('d%'); //same as '1d100', 'd100', or '1d%'
console.log(chance.result); //random number between 1 and 100 (inclusive)

Simple calculation (+, -, *, /):

var attack = roll.roll('2d6+2');
console.log(attack.result); //random number between 3 and 8 (inclusive)

Seeing what was rolled, rather than the sum:

var yahtzee = roll.roll('5d6');
console.log(yahtzee.rolled); //yahtzee.rolled will return something like [5, 2, 4, 6, 1] rather than the sum

var blessedSneaker = roll.roll('2d20b1+1d4+5');
console.log(blessedSneaker.rolled); // blessedSneaker.rolled will return an array containing an array for each component that is a roll of the dice, in the order in which they occurred, e.g. [[19,3],[1]]

Getting the highest two dice of the set:

var pickBestTwo = roll.roll('6d20b2'); //roll 6 dice and give me the 2 highest
console.log(pickBestTwo.calculations[1]); //pickBestTwo.calculations[0] is the same as .result, .calculations[1] is prior to the sum operation

Processing rolls without parsing a string:

var attack = roll.roll({
    quantity: 2,
    sides: 6,
    transformations: [ //can list n-number of pipeline operations to perform on the result
      'sum', //take the array of rolled dice and sum them together
      ['add', 2] //add 2 to the sum
console.log(attack.result); //random number between 3 and 8 (inclusive)

Using custom transformations:

var dropOnes = function(results){
  return results.filter(function (result) {
    return result !== 1;
var noOnes = roll.roll({
  quantity: 5,
  sides: 4,
  transformations: [
    dropOnes, // remove any 1s because we have teh lucky bootz

Using a custom seed:

var srand = require('srand'); // (npm install srand)

roll = new Roll(function () {
  return srand.random();


Validating user input:

var userInput = 'this isn\'t a valid roll',
  valid = roll.validate(userInput);

if (!valid) {
  console.error('"%s" is not a valid input string for node-roll!', userInput);


Inspired by Phillip Newton's Games::Dice.


MIT License


Troy Goode (