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How State Management works? Dead simple SM in Vanilla JavaScript

Vijay Pushkin on March 09, 2021

Dead simple State Management in Vanilla JavaScript It's been years now since you started using Redux, MobX or even plain React Hooks and have no id...

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artydev • Mar 10 '21 • Edited

Here is an optimised version :-)

import {render, html} from 'uhtml';

const App = (function () {

  const State = {
    counter : 0
  }

  function incer () {
    State.counter += 1;
    App.redraw()
  }

  function view () {
    return html`
      <h1>${State.counter}</h1>
      <button class="counter" onclick=${incer}>INC</button>
      <input value = "not erased"/>`
  }

  function redraw () {
    render(app, view())
  }

  return { redraw }

})()

App.redraw()

You can test it here : SSMOPT

artydev • Mar 10 '21

And if you want to get a little further

import {render, html} from 'uhtml';


const Header = () => html`<h1>Header</h1>`
const Footer = () => html`<h1>Footer</h1>`
const Counter = (state, actions) => html`
      <h1>${state.counter}</h1>
      <button class="counter" onclick=${actions.inc}>INC</button>
      <input value = "not erased"/>`

const App = (function () {

  const State = {
    counter : 0
  }

  const Actions = {
    inc : () =>  {
      State.counter += 1;
      redraw();
    }
  }

  function view (s, a) {
    return html`
      ${Header()}
      ${Counter(s, a)}
      ${Footer()}
    `
  }

  function redraw () {
    render(app, view(State, Actions))
  }

  return { redraw }

})()

App.redraw()

You can test it here IntroSamPattern

Reena Verma • Jun 21 '23

Hi @artydev- this is really interesting. I've not heard of the uthml package before. What exactly is it used/needed for vs the original package?

artydev • Mar 10 '21

Thank you for your post.

Here is a variation :

const App =(function () {

  const State = {
    counter : 0
  }

  function render () {
    app.innerHTML = view ();
    return App
  }

  function incer () {
    State.counter += 1;
    App
      .render()
      .setupEvents();
  }

  function view () {
    return `
      <div>Counter ${State.counter}</div>
      <button class="counter">INC</button>
    `
  }

  function setupEvents () {
  let button = 
    document
      .querySelector(".counter")
      .addEventListener("click", App.incer)
  }

  return { render, incer, setupEvents }

})();

App
  .render()
  .setupEvents();

You can test it here : SSM

Regards

Vijay Pushkin • Mar 13 '21

This one is great. Makes better use of functional programming.

Ryan Leach • Mar 10 '21

I don't want to come off sounding like an asshole, but is this satire?

It feels like someone whose never learnt JavaScript, and just copied react examples suddenly learnt how the language works... Unless I'm missing something fundamental.

artydev • Mar 11 '21

Please, be comprehensive...

rjegge • Jun 10 '22

Are you sure you didn't want to come off sounding that way? I'm pretty sure you did.

Viridi • Mar 12 '21 • Edited

Hi Vijay Pushkin,

I know this tutorial is not about the best code but I couldn't help myself from refactoring your code ;).

<!DOCTYPE html>
<html lang="en">
<head>
    <title>State Management in Vanilla JS</title>
</head>
<body>
<div id="app"></div>
<script>
  const App = {
    state: {
      count: 0,
    },
    template() {
      return `
          <h1>Hello Vanilla JS!</h1>
          <div>
            Example of state management in Vanilla JS
          </div>
          <br />
          <h1 id="counter">${this.state.count}</h1>
          <button id="button">Increase</button>
        `;
    },
    initialize(){
      document.getElementById('app').innerHTML = this.template();
      document.getElementById("button").addEventListener("click", () => App.increment());
    },
    increment() {
      this.state.count++;
      this.updateUI();
    },
    updateUI(){
      document.getElementById('counter').textContent = this.state.count;
    }
  };
  App.initialize();
</script>
</body>
</html>

Jiminikiz • Oct 14 '22

<!DOCTYPE html>
<html lang="en">
  <head>
      <title>State Management in Vanilla JS</title>
  </head>
  <body>
    <main id="app">
    </main>
    <script id="template" type="text/template">
      <h1>{{title}}</h1>
      <h2 id="counter">{{count}}</h2>
      <button id="button">Increase</button>      
    </script>
    <script>
      const App = {
        state: {
          title: 'State Counter Example',
          count: 0,
        },
        template() {
          return template.innerHTML
            .replace('{{title}}', App.state.title)
            .replace('{{count}}', App.state.count);
        },
        initialize(){
          app.innerHTML = this.template();
          button.addEventListener("click", () => App.increment());
        },
        increment() {
          this.state.count++;
          this.render();
        },
        render(){
          counter.textContent = this.state.count;
        }
      };

      App.initialize();
    </script>
  </body>
</html>

Afisunlu Dapo • Jun 1 • Edited

"app" in "app.innerHTML" has no reference, even though the code works perfectly. Can you please enlighten me? Pardon me me for being a novice. I was expecting something like app = document,getElementById("app")

Jiminikiz • Jun 1

Hey Afisunlu, totally a valid question:

Both app and template exist because each DOM node that has a defined id attribute gets added to the global window object and therefore is able to be referenced without explicit initialization. This is part of the reason why id attributes should be unique for each DOM node in the tree.

Try it with another DOM node and a different id!

Yogini Bende • Mar 9 '21

This is a nice explaination and it helps you understand the state management concept behind the scene. Good work 🙌

artydev • Mar 11 '21 • Edited

Hello,

here is the code of utml (877lines)

uhtml.js

You can test it here : uhtmltest

Optimized in a sense, it uses VDom Diff to update the page.

Regards

Nicholas Mendez • Mar 10 '21 • Edited

So happy to see some framework-agnostic content. This is a great read and shows sometimes we can get by just fine with the standard web technologies.

I was really wondering why you had _App and App but your justification is brillaint.

John Grisham • Mar 16 '21 • Edited

Vanilla javascript? I've never heard of that library.

Salvatore Sferrazza • May 7 '23

Really into this, thank you for sharing! The cognitive burden of many frameworks is too high for what one gets in return.

I've found this routine to be helpful for rendering the state of arbitrary objects to the DOM. Additionally, when using standard HTML template tags, I've used another routine to populate slots (template parameters) and render the template at runtime.

Samuel Henshaw • Mar 10 '21

Great insight

jim shtepa • Mar 11 '21

Is your lastname really Pushkin? Like Alexander Sergeyevich Pushkin?

Vijay Pushkin • Mar 12 '21

The place where I'm from, we don't have family names. So, yes both are my names!

jim shtepa • Mar 12 '21

Understood, cool. Pushkin is perhaps the greatest person in Russian literature. I am from Kazakhstan and we happen to speak and learn russian language at school. Anyways you have a great name!

Saksham96 • Mar 10 '21

Nice Insight on state management, waiting for the upcoming article.

chovy • Nov 19 '21

When's the next article which I hope will be web components leverage native shadow Dom to handle updates when state changes :)

Nice article by the way. Good starting point.

Param Siddharth • Mar 11 '21 • Edited

Wow! 😮😍🥰 What an amazing tutorial! Now I can start writing my own front-end web framework. 😏😏😂😂 Just kidding, I won't! But I've always wanted to know how to. Thank you for the article! 💕💕

ankitakathuria • Nov 15 '22

hey what does it mean when you add redraw in curly braces i.e return {redraw}. Please someone explain