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

crustate

v0.9.1

Published

Crustate is a message-based modular state-management library.

Downloads

36

Readme

Crustate

npm bundle size Dependencies Build Status Codecov License npm Greenkeeper badge

This library is based on the principles of message passing found in languages like Elm and Elixir/Erlang. The purpose is to be able to build modular state with controlled side-effects through messaging.

Model

type Model<T, I, M: Message> = {
  id: string,
  init: (init: I) => Update<T>,
  update: (state: T, msg: M | UnknownMessage) => ?Update<T> | UpdateNoop,
};

A model represents how a state is initialized and updated, as well as which messages it will respond to at any given moment.

Message

type Message = { +tag: string };

A message is just plain data, a JavaScript object, with a mandatory property named tag. The tag is supposed to work as a discriminator, informing the receivers of what type of message it is, what possible data it contains, and what it means.

Note that these messages are to be completely serializable by JSON.stringify to facilitate resumable sever-rendering, logging, history playback, inspection, and other features.

const ADD = "add";

let msg = {
  tag: ADD,
  value: 2,
};

Init

type ModelInit<T, I> = (init: I) => Update<T>;

The initial data of the state, accepts an optional init-parameter.

import { updateData } from "crustate";

function init() {
  return updateData(0);
}

Update

type ModelUpdate<T, M: Message> = (state: T, msg: M) => ?Update<T>;

Conceptually update is responsible for receiving messages, deciding on if the state should respond to them, interpreting them, updating the state, and send new messages in case other components need to be informed or additional data requested.

This is very similar to Redux's Reducer concept with the main difference being that the update-function can send new messages as well as not return anything to indicate that the state is not interested in the message.

function update(state, message) {
  switch (message.tag) {
    case ADD:
      return updateData(state + message.value);
  }
}

When a message produces an update-value from a state update it will be consumed by that state and no longer propagate upwards in the tree, a null/undefined return means that the message should keep propagating upwards.

Messages sent from the update function are propagated upwards in the state-hierarchy and can be acted upon in supervising states.