pick-random-weighted

Simple, fast and lightweight function to pick a random element from a weighted array.

Install
Usage
Randomness
Contributing
Support

Install

npm install pick-random-weighted

Usage

The package contains a pick function that just works out-of-the box.

import pick from 'pick-random-weighted';

const colors = [
	['Red', 30],
	['Green', 20],
	['Blue', 40]
];

const color = pick(colors);

It also contains a Picker class that can be instantiated to create a custom picker.

import { Picker } from 'pick-random-weighted';

const picker = new Picker();
const colors = [
	['Red', 30],
	['Green', 20],
	['Blue', 40]
];

const color = Picker.pick(colors);

pick(values)

Returns a random value from the values array.

values

Type: Array

List of values to pick from.

Each element should be provided in the format [value, weight].

Random number generation

By default, and to keep a small footprint, the library uses Math.random() to generate the random number to pick the value.

If you need you can define a custom function to generate random values, you can create a function that returns fixed values to use on your unit tests or implement a more specialized library like random-js.

Using a custom random generator

By overwriting pick.random you can define your custom function.

Remember the returned value should be a number within the [0,1) range.

import { Picker } from 'pick-random-weighted';

const picker = new Picker(function () {
	return 0.3;
});

const colors = [
	['Red', 30],
	['Green', 20],
	['Blue', 40]
];

const color = Picker.pick(colors);
// Will always return 'Green' since our custom random generator function always returns the same value.

Contributing

Contributions are always welcome! Please run npm test beforehand to ensure everything is ok.

Support

If you use this package please consider starring it :)

alvarocastro/pick-random-weighted