alanmacleod/bit-meddler

Very quickly scramble (shuffle?) a range of integers via a linear feedback shift register implementation. Thrilling 😐

bit-meddler

Returns randomish integers in a given range.

The practical use of this package doesn't reveal itself until you go for stupid big-ass numbers. Like 100,000 which would take a relatively long time and waste a ton of memory to iterate through and return each integer only once using Math.random() and a flags array.

Watch a live demo here

If Bette Midler ever needed a lightweight method to scramble a range of numbers without resorting to a random number generator or an array, oh boy, she would surely:

npm install --save bit-meddler

...and to scramble those numbers between, say, 1 and 1000:

let bitmeddler = require('bit-meddler');

let meddle = new bitmeddler(1000)

meddle.next(); // give me a number

Calling .next() will return every number between 1 and 1000 in a scrambled, pseudorandom order. The method will return a null once every number has been returned. You can then call .reset() to start again if you wish.

An optional second parameter is a seed number to vary the order:

let seed = 42;
let meddle = new bitmeddler(1000, seed);

If you just want access to the full list of numbers, there's a convenient all method for that:

let meddle = new bitmeddler(1000);

let scrambled = meddle.all(); // return array of 1000 scrambled integers

So it's not "very random" but produces a passable simulation if speed and low memory usage are amongst your requirements. It uses a linear feedback shift register design adapted for software. I remember writing games as a kid on bait hardware bending my brain trying to think of a way to do this without an array. So thanks to this book Game Engine Black Book: Wolfenstein 3D for finally revealing the method to me years later. And also this website was handy.