cjheath/math.random.js

A better random number generator for Javascript, and add-ons

math.random.js - A better random number generator for Javascript

Rationale

Most browsers have implementations of Math.random that are based on the C runtime library's 'rand' function. This function is commonly a simple linear congruential pseudo-random number generator, often with a period of only 2^32-1. Besides that, the method used results in successive numbers having poor randomness (spectral behaviour) in the least significant bits.

This module replaces Math.random with a PRNG that has more stored state, a period of about 2^116, and which passes the BigCrush test, but is still very fast.

The core of the generator is Alea, courtesy of Johannes Baagoe baagoe@baagoe.com, and you should heed the advice and warnings here.

Synopsis

Math.random()

Works just like the built-in, except it's more random.

Math.random.uint32()

Returns a random number that's guaranteed to be a non-negative 32-bit integer

Math.random.fract53()

Returns a random number that's guaranteed to be a fraction between 0 and 1, with 53 bits of entropy.

Math.random.seed(...)

Adds additional seed data to the pseudo-random number generator. Any arguments are allowed (they'll be converted to String before being processed), otherwise Date will be used. In a Javascript application, you might occasionally call:

Math.random.seed(event.timestamp)

Math.random.uuid()

Returns a new UUID (GUID) in string form, like "0db3c449-24a8-6efe-3e8e-4c0c85ba447a".

Status

Stable.