https://github.com/alvarocastro/pick-random-weighted
Ultra fast and lightweight function to pick a random item from a weighted list.
https://github.com/alvarocastro/pick-random-weighted
array arrays choose decision-making javascript random weighted weighted-random
Last synced: about 2 months ago
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Ultra fast and lightweight function to pick a random item from a weighted list.
- Host: GitHub
- URL: https://github.com/alvarocastro/pick-random-weighted
- Owner: alvarocastro
- License: mit
- Created: 2019-07-18T18:39:13.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2023-04-05T21:57:37.000Z (about 2 years ago)
- Last Synced: 2025-04-12T06:44:00.373Z (about 2 months ago)
- Topics: array, arrays, choose, decision-making, javascript, random, weighted, weighted-random
- Language: JavaScript
- Homepage: https://www.npmjs.com/package/pick-random-weighted
- Size: 1.04 MB
- Stars: 7
- Watchers: 1
- Forks: 1
- Open Issues: 9
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# pick-random-weighted
[](https://www.npmjs.com/package/pick-random-weighted)
[](https://github.com/alvarocastro/pick-random-weighted/actions?query=workflow%3Abuild)
[](https://codeclimate.com/github/alvarocastro/pick-random-weighted/maintainability)
[](https://coveralls.io/github/alvarocastro/pick-random-weighted?branch=master)
[](https://bundlephobia.com/result?p=pick-random-weighted)
[](https://github.com/xojs/xo)
[](https://github.com/semantic-release/semantic-release)Simple, fast and lightweight function to pick a random element from a weighted array.
- [Install](#install)
- [Usage](#usage)
- [Randomness](#random-number-generation)
- [Contributing](#contributing)
- [Support](#support)## Install
```bash
npm install pick-random-weighted
```## Usage
The package contains a `pick` function that just works out-of-the box.
```js
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.
```js
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](https://www.npmjs.com/package/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.```js
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 :)