npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

random-elements

v0.4.3

Published

Utility for picking one or more elements from any array

Downloads

18

Readme

Random Element picker

Provides a nicely-typed, well-tested utility for picking one or multiple random element(s) from an array.

Pretty simple.

The main benefits of this over doing it yourself:

  • Proper TypeScript generics ensure that the type of element array you submit is returned with the same types. Makes the compiler happy when you use this library in your own code.
  • Well tested, so prevents silly range errors and unexpected results.

Simple random picking:

  • pickRandomIndex
  • pickRandomIndexes
  • pickRandomElement (type safe arrays! no mutation!)
  • pickMultipleRandomElements (same as above, but returns multiple elements)

Example

const myArray = ["one", "two", "three"];
const answer = pickRandomElement(myArray);

// Typescript will know that "answer" is a string

Weighted distributions:

Sometimes you want to weight certain outcomes more or less likely than others. This library lets you pass a Map of keys with relative probabilities (weights), and each time you call the function, you will get a single key back but with the probabilities stacked in favour of the ones you weighted higher.

  • pickKeysWithWeights

Examples

Note the different ways of building the Map object; either construct an empty one and set some elements (Example 1), or do it in one go, in the constructor (Example 2).

Example 1

const weights = new Map();
weights.set("one", 1);
weights.set("two", 1);
weights.set("three", 2);

const pick = pickKeysWithWeights(weights);

// Expect to get "three" roughly twice as often compared to "one" or "two". 
// The chances of getting "three" any given time is 50%, however - 
// that's probability, folks!

Example 2

const weights = new Map([
  ["heads", 2],
  ["tails", 1]
]);

const pick = pickKeysWithWeights(weights);

// Expect to get "heads" roughly twice as often as "tails". That means 
// 66.6% chance vs 33.3% chance, right?