README
dicekit-fp
A functional-programming-friendly library for rolling virtual dice. It provides pure-functional way to create random numbers and dice (functions that create random integers), combine and modiify the dice results, and convert strings like "2d6+2" to functions. It has no dependencies and is about 2KB minified.
Instead of using objects, the library creates random number generators based on the parameters you provide. The library uses higher-order functions to modify the results in order to modify or multiply the results of the dice rolls. Most of the functions return a () => number
(aliased in the Typescript code as NumberGenerator
).
The functions that produce random numbers, such as createDie()
, typicially have two versions: one that takes a random number generator (RNG) as the first parameter and have the suffix With
as in createDieWith()
, the other which is already seeded with Math.random()
as the RNG as in createDie()
Use
createDie()
Create a basic die with // takes a number of faces for the die as an argument and returns a function that generates ints.
const d6 = createDie(6);
// random int between 1 and 6
d6();
You can use any number (>=2) of faces
const coinFlip = createDie(2);
const devilDie = createDie(666);
createDice()
Create multiple dice with a modifier in one step using // takes a number of faces, number of dice (default 1), and modifier (default +0)
// 2d6+3
const _2d6plus3 = createDice(6, 2, 3);
// Random result of rolling 2 six sided dice and adding 3 to the result.
// (1..6) + (1..6) + 3
_2d6plus3();
// Note, this is not the same as a random int between 5..15.
// Because each die gets rolled independently, the results are more likely to follow a normal distribution curve favoring the middle numbers (like 7) more than the edge numbers (like 2 and 12)
// 2d6+0
const _2d6 = createDice(6, 2);
// 1d6+0
const _1d6 = createDice(6);
combineDice()
Combine multiple dice functions with const d6 = createDie(6);
const d8 = createDie(8);
// always returns 2
const two = () => 2;
// 2d6+1d8+2
const _2d6_1d8_2 = combineDice([d6, d6, d8, two]);
// generate random int
// (1..6) + (1..6) + (1..8) + 2
_2d6_1d8_2();
Dice Strings
Using parseDiceString(s)
will convert a string into a function that rolls dice based on the input. The format of the string is inspired by Tabletop RPG dice notation.
${multiplier}d${sides}+${modifier}
Where:
multiplier
is the number of dice (default is 1)- Use
d
orD
to separate the multiplier from the number of sides on the dice. sides
is the number of sides on the dice. The range will be1
tosides
, inclusive.modifier
is an integer to add to the total
Examples
- "d6" -> roll one 6-sided-die`
- "2d6" -> roll two 6-sided-dice and sum results`
- "3d6+2" -> roll three 6-sided-dice, add 2 to the sum.`
- "2d12-2" -> roll two 12-sided-dice, subtract 2 from the sum.`
- "1d12-5+2d20+4+d4" -> roll one 12-sided-die, two 20-sided-dice, and one 4-sided-die, subtract 5 and add 4 to the sum.`
Whitespace and letter case are ignored.
createCustomDie()
Custom dice with To create a die that isn't typical, you can use createCustomDie()
and provide an array of dice face values.
// Generate a random color string
const colors = ["red", "orange", "yellow", "green", "blue", "indigo", "violet"];
const colorDie = createCustomDie(colors);
colorDie(); // "blue"
// Create a die that lands on 6 more often.
const weightedD6 = createCustomDie([1, 2, 3, 4, 5, 6, 6, 6]);
weightedD6(); // 6, probably
// If the values are numerical, they can be combined with other dice functions...
const weightedDice = combineDice([weightedDie, weightedDie]);
Custom Random seed
All the fuctions that rely on a random number generator come with a version that uses Math.random
for the RNG. To use a different generator, use the alternate versions with the suffix With
as in createDieWith(f)
where f
is a function that takes no arguments and returns a number, n
, where 0.0<=n<1.0
const myRNG = randomSeed.create("my seed");
const createDieSeeded = createDieWith(myRNG);
const d6 = createDieSeeded(6);
d6(); // uses myRNG for generating numbers.
Other functions
TBD. Meanwhile, please review test
folder for examples.
Below this line is boilerplate from TSDX
=====
Library bootstrapped with TSDX
For more info, see tsdx.io
Commands
TSDX scaffolds your new library inside /src
.
To run TSDX, use:
npm start # or yarn start
This builds to /dist
and runs the project in watch mode so any edits you save inside src
causes a rebuild to /dist
.
To do a one-off build, use npm run build
or yarn build
.
To run tests, use npm test
or yarn test
.
Configuration
Code quality is set up for you with prettier
, husky
, and lint-staged
. Adjust the respective fields in package.json
accordingly.
Jest
Jest tests are set up to run with npm test
or yarn test
.
You can also use yarn test --watch
or yarn test --coverage
Bundle Analysis
size-limit
is set up to calculate the real cost of your library with npm run size
and visualize the bundle with npm run analyze
.
Rollup
TSDX uses Rollup as a bundler and generates multiple rollup configs for various module formats and build settings. See Optimizations for details.
TypeScript
tsconfig.json
is set up to interpret dom
and esnext
types, as well as react
for jsx
. Adjust according to your needs.
Continuous Integration
GitHub Actions
Two actions are added by default:
main
which installs deps w/ cache, lints, tests, and builds on all pushes against a Node and OS matrixsize
which comments cost comparison of your library on every pull request usingsize-limit
Optimizations
Please see the main tsdx
optimizations docs. In particular, know that you can take advantage of development-only optimizations:
// ./types/index.d.ts
declare var __DEV__: boolean;
// inside your code...
if (__DEV__) {
console.log("foo");
}
You can also choose to install and use invariant and warning functions.
Module Formats
CJS, ESModules, and UMD module formats are supported.
The appropriate paths are configured in package.json
and dist/index.js
accordingly. Please report if any issues are found.
Named Exports
Per Palmer Group guidelines, always use named exports. Code split inside your React app instead of your React library.
Including Styles
There are many ways to ship styles, including with CSS-in-JS. TSDX has no opinion on this, configure how you like.
For vanilla CSS, you can include it at the root directory and add it to the files
section in your package.json
, so that it can be imported separately by your users and run through their bundler's loader.
Publishing to NPM
We recommend using np.