🗄️ almy

The simpliest store for managing the state in your application.
Works in all environments and all browsers.

Why do I need a centralized state management

Managing the information rendered is difficult, mostly when our apps grow large and the state is scattered across many components and the interactions between them without control.

To solve this, the current state of the art solution is to use a globalized state where we can centralize and have more control over the information we have to render. Almy is a simple library that uses a pub/sub façade along with a centralized state management which makes the the side effects of changing information easy to control and eliminates the risk of getting race conditions in our applications.

Installation

npm install --save almy

Methods

• dispatch(key: string, value: any)
  Dispatches some event that happened in a key value fashion
• subscribe(key: string, callback: Function)
  Subscribes to dispatched events. If someone has dispatched an event before, it calls the callback right away
• state(key:?string):Object
  Returns the state of your application

Usage

Including it as a script tag

<script src="./node_modules/almy/dist/almy.umd.js"></script>
<script>
  almy.almy.dispatch('window_width', 524)
</script>
<script>
  almy.almy.subscribe('window_width', function(newWidth) {
    //Do something with the new width
  })
</script>

Including it as a module

<div id="content"></div>
<script type='module'>
    import {almy} from './node_modules/almy/dist/almy.esm.js'

    almy.subscribe('user->name', (username) => {
        document.getElementById('content').textContent = username;
    });

    almy.dispatch('user', {id: 1, name: 'nick'})
</script>

Using in a node environment

const { almy } = require('almy')
almy.subscribe('cpu_usage', function(newCpuUsage) {
    //Do something with the new cpu usage
})

//In some other place in your code
almy.dispatch('cpu_usage', 9000)

You can also dispatch objects:

const { almy } = require('almy')
almy.subscribe('cpu', function(cpu) {
    console.log(cpu.temperature)
})

almy.dispatch('cpu->temperature', 65)

Or subscribe to objects properties and receive every change:

almy.subscribe('cpu->ips', function(ips) {
    console.log('Intructions per seconds are '+ips)
});
...

almy.dispatch('cpu', {ips: 1})

...

almy.dispatch('cpu', {ips: 5})

// This would ouput:
// "Intructions per seconds are 1"
// "Intructions per seconds are 5"

Limitations

Only one object deepness subscriptions are supported. Example:

almy.dispatch('user', {favorites: {televisions: {'4k': true}}})

// This doesn't work
almy.subscribe('user->favorites->televisions->4k', value => {
    
})

// This does work
almy.subscribe('user->favorites', favorites => {
    if (favorites.televisions['4k']) {
        
    }
})

A flatten state is easier to reason and understand.

Other state management libraries

• Vuex: https://github.com/vuejs/vuex
• Redux: https://github.com/reduxjs/redux
• Flux: https://github.com/facebook/flux

References

Worlds: Controlling the Scope of Side Effects http://www.vpri.org/pdf/tr2011001_final_worlds.pdf