random-seed

What is random-seed?

The random-seed npm package is used to generate random numbers based on a seed value. This allows for reproducible random number sequences, which can be useful in scenarios like testing, simulations, and procedural content generation.

What are random-seed's main functionalities?

Seeded Random Number Generation

This feature allows you to create a random number generator that produces the same sequence of random numbers for a given seed. This is useful for reproducibility in tests and simulations.

const randomSeed = require('random-seed');
const seed = 'my-seed';
const rand = randomSeed.create(seed);
console.log(rand.random()); // Generates a random number based on the seed

Random Integer Generation

This feature allows you to generate a random integer within a specified range, based on the seed. This can be useful for scenarios where you need random but reproducible integers.

const randomSeed = require('random-seed');
const seed = 'my-seed';
const rand = randomSeed.create(seed);
console.log(rand.intBetween(1, 100)); // Generates a random integer between 1 and 100 based on the seed

Random Float Generation

This feature allows you to generate a random floating-point number within a specified range, based on the seed. This can be useful for simulations and procedural content generation.

const randomSeed = require('random-seed');
const seed = 'my-seed';
const rand = randomSeed.create(seed);
console.log(rand.floatBetween(0, 1)); // Generates a random float between 0 and 1 based on the seed

Other packages similar to random-seed

seedrandom

The seedrandom package provides a similar functionality to random-seed, allowing for seeded random number generation. It offers more features, such as the ability to generate random numbers with different algorithms (e.g., Alea, XOR128, etc.). It is also widely used and well-documented.

random-js

The random-js package is a versatile random number generator library that supports seeding. It provides a variety of random number generation methods, including integers, floating-point numbers, and booleans. It also supports different distributions, such as uniform and normal distributions.

chance

The chance package is a comprehensive random generator helper for JavaScript. It supports seeded random number generation and offers a wide range of random data generation capabilities, including names, addresses, and other complex data types. It is highly customizable and well-suited for testing and data generation.

README

random-seed

Gibson Research Corporation's Ultra-High Entropy Pseudo-Random Number Generator ported to node.

The original library / project page is located here: https://www.grc.com/otg/uheprng.htm

The node project page is here: https://github.com/skratchdot/random-seed

There were a few modifications made to the original library to allow seeding, and to pass jshint.

Getting Started

Install the module with: npm install random-seed

var rand = require('random-seed').create();
var n = rand(100); // generate a random number between 0 - 99

Documentation

Create a random number generator

var gen = require('random-seed'); // create a generator

// these generators produce different numbers
var rand1 = gen.create(); // method 1
var rand2 = new gen();    // method 2
var rand3 = gen();        // method 3

// these generators will produce
// the same sequence of numbers
var seed = 'My Secret String Value';
var rand4 = gen.create(seed);
var rand5 = new gen(seed);
var rand6 = gen(seed);

Random Generator Methods

Once a random generator is created, you have the following methods available.

I typically create a random generator like this:

var rand = require('random-seed').create();

rand(num)

rand.seed(seed)

Same as calling rand.initState() followed by rand.hashString(seed). If seed is not a string, then the seed value will be converted to a string. If you don't pass a seed argument, then the generator uses Math.random() as the seed.

rand.string(count)

Returns a pseudo-random string of 'count' printable characters ranging from chr(33) to chr(126) inclusive.

rand.cleanString(inStr)

Removes leading and trailing spaces and non-printing control characters, including any embedded carriage-return (CR) and line-feed (LF) characters, from any string it is handed. This is also used by the 'hashstring' function (below) to help users always obtain the same EFFECTIVE uheprng seeding key.

rand.hashString(inStr)

Hashes the provided character string after first removing any leading or trailing spaces and ignoring any embedded carriage returns (CR) or Line Feeds (LF).

rand.addEntropy(/* accept zero or more arguments */)

This handy exported function is used to add entropy to our uheprng at any time.

rand.initState()

If we want to provide a deterministic startup context for our PRNG, but without directly setting the internal state variables, this allows us to initialize the mash hash and PRNG's internal state before providing some hashing input.

rand.done()

We use this (optional) exported function to signal the JavaScript interpreter that we're finished using the internal "Mash" hash function so that it can free up the local "instance variables" it will have been maintaining. It's not strictly necessary, of course, but it's good JavaScript citizenship.

Examples

Default Usage: print 1 random number between 0 - 99

var rand = require('random-seed').create();
var n = rand(100); // generate a random number between 0 - 99

Always print same sequence of random numbers

var rand = require('random-seed').create();
rand.initState();
var n1 = rand(100); // n1 === 58
var n2 = rand(100); // n2 === 26
rand.initState();   // re-init
var n3 = rand(100); // n3 === 58 && n3 === n1

Create 2 random number generators

var rand1 = require('random-seed').create(),
	rand2 = require('random-seed').create();
console.log(rand1(100), rand2(100));

Create 2 random number generators with the same seed

var seed = 'Hello World',
	rand1 = require('random-seed').create(seed),
	rand2 = require('random-seed').create(seed);
console.log(rand1(100), rand2(100));

Release History

• v0.1.0 (Released October 26, 2013)

License

Copyright (c) 2013 skratchdot

Dual Licensed under the MIT license and the original Public Domain License by GRC.