prnguin

This module contains a small collection of simple "generators", i.e. pure functions that transform a number into a predictable output value. You will usually want to change the seed after every use (typically by incrementing it) unless your goal is to get the same results multiple times.

Since generators are just functions, crafting your own custom generators to match specific scenarios is a trivial matter. For example, the following generator simulates the rolling of a six-sided die.

function roll(seed) {
  return integer(1, 6, seed)
}

Additionally, all the functions in this module derive their seemingly random nature from percent, further demonstrating their composability.

usage

const { percent, integer, boolean, pick, shuffle } = require("prnguin")

Alternatively, you can import the modules you want individually:

const percent = require("prnguin/percent")

percent(seed)

Generate a number between 0 and 1 using seed, exclusively.

if (percent(seed++) < 0.1) {
  money.type = 'gold'
} else {
  money.type = 'copper'
}

1 is not included in the set of possible return values, so this function is essentially a seedable version of Math.random().

integer(min, max, seed)

Generate an integer between min and max using seed, inclusively.

> integer(1, 10, seed++)
6

Unlike percent, the upper number (max) is included in the set of possible return values.

boolean(seed)

Choose either true and false based on the given seed.

if (boolean(seed++)) {
  for (let connector of connectors) {
    floors.push(connector)
  }
} else {
  let connector = pick(connectors, seed++)
  doors.push(connector)
}

pick(array, seed)

Chooses a random element from array using seed.

let card = pick(deck, seed++)

shuffle(array, seed)

Shuffles the items in array in place using seed.

shuffle(deck, seed++)

shuffle also returns the mutated array, courtesy of Array.prototype.sort.

license

MIT © Brandon Semilla