A presentation at Riviera Dev in in Sophia Antipolis, France by Horacio Gonzalez
WebComponents in 2023: A Complete Exploration Horacio Gonzalez 2023-07-10
Who are we? Introducing myself and introducing OVHcloud
Horacio Gonzalez @LostInBrittany Spaniard Lost in Brittany
OVHcloud Web Cloud & Telcom 30 Data Centers in 12 locations 1 Million+ Servers produced since 1999 Private Cloud 34 Points of Presence on a 20 TBPS Bandwidth Network 1.5 Million Customers across 132 countries Public Cloud 2200 Employees worldwide 3.8 Million Websites hosting Storage 115K Private Cloud VMS running 1.5 Billion Euros Invested since 2016 300K Public Cloud instances running P.U.E. 1.09 Energy efficiency indicator 380K Physical Servers running in our data centers 20+ Years in Business Disrupting since 1999 Network & Security
We want the code! https://github.com/LostInBrittany/web-components-in-2023/
What the heck are web component? The 3 minutes context
Web Components Web standard W3C
Web Components Available in all modern browsers: Firefox, Safari, Chrome
Web Components Create your own HTML tags Encapsulating look and behavior
Web Components Fully interoperable With other web components, with any framework
Web Components CUSTOM ELEMENTS SHADOW DOM TEMPLATES
Custom Element To define your own HTML tag <body> … <script> window.customElements.define(‘my-element’, class extends HTMLElement {…}); </script> <my-element></my-element> </body>
Shadow DOM To encapsulate subtree and style in an element <button>Hello, world!</button> <script> var host = document.querySelector(‘button’); const shadowRoot = host.attachShadow({mode:’open’}); shadowRoot.textContent = ‘こんにちは、影の世界!’; </script>
Template To have clonable document template <template id=”mytemplate”> <img src=”” alt=”great image”> <div class=”comment”></div> </template> var t = document.querySelector(‘#mytemplate’); // Populate the src at runtime. t.content.querySelector(‘img’).src = ‘logo.png’; var clone = document.importNode(t.content, true); document.body.appendChild(clone);
But in fact, itʼs just an element… ● ● ● ● Attributes Properties Methods Events
Sometimes I feel a bit grumpy The stories of the grumpy old speaker…
On Polymer tour since 2014
Image: bu.edu Web components == Revolution
Images: BitRebels & Brickset Building a world brick by brick
Is the promise unfulfilled? It’s 2023 now, where is your revolution, dude?
Is it a conspiracy?
Am I only a dreamer?
Well, revolution IS there But it’s a silent one…
I as looking for a great example
New Reddit runs on Web Components
Often hidden in plain sight
Vanilla Web Components
Let’s build a vanilla Web Component Using only HTML, CSS & JS, no library needed
A very basic web component class HelloWorld extends HTMLElement { // This gets called when the HTML parser sees your tag constructor() { super(); // always call super() first in the ctor. this.msg = ‘Hello World!’; } // Called when your element is inserted in the DOM or // immediately after the constructor if it’s already in the DOM connectedCallback() { this.innerHTML = <p>${this.msg}</p>; } } customElements.define(‘hello-world’, HelloWorld);
Custom Elements: ● Let you define your own HTML tag with bundled JS behavior ● Trigger lifecycle callbacks ● Automatically “upgrade” your tag when inserted in the document
Custom Elements donʼt: ● Scope CSS styles ○ Shadow DOM ● Scope JavaScript ○ ES2015 ● “Reproject” children into <slot> elements ○ Shadow DOM
Adding ShadowDOM class HelloWithShadowdom extends HTMLElement { // This gets called when the HTML parser sees your tag constructor() { super(); // always call super() first in the ctor. this.msg = ‘Hello World from inside the ShadowDOM!’; this.attachShadow({ mode: ‘open’ }); } // Called when your element is inserted in the DOM or // immediately after the constructor if it’s already in the DOM connectedCallback() { this.shadowRoot.innerHTML = <p>${this.msg}</p>; } } customElements.define(‘hello-with-shadowdom’, HelloWithShadowdom);
Using web components <!DOCTYPE html> <html> <head> <title>Vanilla Web Components</title> <script src=”./hello-world.js”></script> <script src=”./hello-with-shadowdom.js”></script> </head> <body> <hello-world></hello-world> <hello-with-shadowdom></hello-with-shadowdom> </body> </html>
Using web components
Lifecycle callbacks class MyElementLifecycle extends HTMLElement { constructor() { // Called when an instance of the element is created or upgraded super(); // always call super() first in the ctor. } static get observedAttributes() { // Tells the element which attributes to observer for changes return []; } connectedCallback() { // Called every time the element is inserted into the DOM } disconnectedCallback() { // Called every time the element is removed from the DOM. } attributeChangedCallback(attrName, oldVal, newVal) { // Called when an attribute was added, removed, or updated } adoptedCallback() { // Called if the element has been moved into a new document } }
my-vanilla-counter element class MyVanillaCounter extends HTMLElement { constructor() { super(); this._counter = 0; this.attachShadow({ mode: ‘open’ }); } connectedCallback() { this.render(); this.display(); } static get observedAttributes() { return [ ‘counter’ ] } // We reflect attribute changes into property changes attributeChangedCallback(attr, oldVal, newVal) { if (oldVal !== newVal) { this[attr] = newVal; } }
my-counter custom element // Getter and setters for counter get counter() { return this._counter; } set counter(value) { if (value != this._counter) { this._counter = Number.parseInt(value); this.setAttribute(‘counter’, value); this.display(); } } increment() { this.counter = this.counter + 1; this.dispatchEvent(new CustomEvent(‘increased’, {detail: {counter: this.counter}})); }
my-counter custom element render() { let container = document.createElement(‘div’); container.style.display = ‘flex’; … this.style.fontSize = ‘5rem’; } display() { this.output.innerHTML = ${this.counter}; } } customElements.define(my-vanilla-counter, MyVanillaCounter);
my-counter-with-templates let template = ` <style> … </style> <div class=”container”> <div id=”icon”> <img src=”${import.meta.url}/../img/logo.png”>
</div> <div id=”value”> 0 </div> </div> `;my-counter-with-templates render() { let templ = document.createElement(‘template’); templ.innerHTML = template; this.shadowRoot.appendChild(templ.content.cloneNode(true)); let button = this.shadowRoot.getElementById(‘icon’); button.addEventListener(‘click’, this.increment.bind(this)); } display() { console.log(this.shadowRoot.getElementById(‘value’)) this.shadowRoot.getElementById(‘value’).innerHTML = ${this.counter}; }
Coding my-counter
my-counter custom element
Why those libs? Why people don’t use vanilla?
Web component standard is low level At it should be!
Standard == basic bricks Standard exposes an API to: ○ Define elements ○ Encapsulate DOM
Libraries are helpers They give you higher-level primitives
Different high-level primitives Each one tailored to a use
Sharing the same base High-performant, low-level, in-the-platform web components standard
Libraries aren’t a failure of standard They happen by design
A library for building reusable, scalable component libraries
Not another library A Web Component toolchain
A build time tool To generate standard web components
Fully featured ● Web Component-based ● Component pre-rendering ● Asynchronous rendering pipeline ● Simple component lazy-loading ● TypeScript support ● JSX support ● Reactive Data Binding ● Dependency-free components
And the cherry on the cake Server-Side Rendering
Stencil leverages the web platform
The Stencil story A company tired of putting good code in the bin
Once upon a time there was a fight Between native apps and web app on mobile
A quest to the perfect solution Hybrid apps, leveraging on web technologies
A company wanted to do it well The perfect technology for mobile web and hybrid apps
The time is 2013 So what technology would you use?
Really soon after launch… Hey folks, we are killing AngularJS!
What did Ionic people do? Let’s put everything in the trash bin and begin anew
But times have changed… In 2013 Angular JS was the prom queen
Times have changed… In 2017 Angular is only one more in the clique
Angular limits adoption of Ionic Devs and companies are very vocal about JS Frameworks
What did Ionic people do? Let’s put everything in the trash bin and begin anew… But on which framework?
What about web components? A nice solution for Ionic problems: Any framework, even no framework at all!
But what Web Component library? SkateJS There were so many of them!
Let’s do something different A fully featured web component toolchain With all the bells and whistles!
Ionic rewrote all their code again From Ionic 4 is fully based on Stencil
Now Ionic works on any framework Or without framework at all
And we have Stencil To use it in any of our projects
Hands on Stencil Simply use npm init npm init stencil Choose the type of project to start ? Select a starter project. Starters marked as [community] are developed by the Stencil Community, rather than Ionic. For more information on the Stencil Community, please see https://github.com/stencil-community › - Use arrow-keys. Return to submit. ❯ component Collection of web components that can be used anywhere app [community] Minimal starter for building a Stencil app or website ionic-pwa [community] Ionic PWA starter with tabs layout and routes
Hands on Stencil And the project is initialized in some seconds! ✔ Pick a starter › component ✔ Project name › my-stencil-counter ✔ All setup in 17 ms $ npm start Starts the development server. $ npm run build Builds your components/app in production mode. $ npm test Starts the test runner. We $ $ $ suggest that you begin by typing: cd my-stencil-counter npm install npm start Happy coding! 🎈
Let’s look at the code
Some concepts import { Component, Prop, h } from ‘@stencil/core’; import { format } from ‘../../utils/utils’; @Component({ tag: ‘my-component’, styleUrl: ‘my-component.css’, shadow: true }) export class MyComponent { @Prop() first: string; Decorators
Some concepts @Prop() first: string; @Prop() middle: string; @Prop() last: string; @State() nickname: string; Properties and States
Some concepts render() { return <div>Hello, World! I’m {this.getText()}</div>; } Asynchronous rendering using JSX
Some concepts @Prop() value: number; @Watch(value) valueChanged(newValue: boolean, oldValue: boolean) { console.log(The new value is ${newValue}, it was ${oldValue} before); }
Watch
Some concepts @Event() actionCompleted: EventEmitter; someAction(message: String) { this.actionCompleted.emit(message); } @Listen(‘actionCompleted’) actionCompletedHandler(event: CustomEvent) { console.log(‘Received the custom actionCompleted event: ‘, event.detail); } Emitting events
Some concepts @Method() async sayHello() { this.hello = true; } render() { return ( <Host> <h2>{ this.hello ? Hello sthlm.js : ”}</h2> </Host> ); }
Asynchronous public methods
Some concepts @Component({ tag: ‘my-component’, styleUrl: ‘my-component.css’, shadow: true }) export class MyComponent { Optional Shadow DOM
Coding my-stencil-counter
Simple. Fast. Web Components
Do you remember Polymer The first Web Component library
It is deprecated… And that means good news!
Let’s try to see clearer Let’s dive into Polymer history…
A tool built for another paradigm No web component support on browsers No React, Angular or Vue innovations
No so well suited for the current one The current platform is way more powerful The state of art has evolved
Let’s learn from its lessons The current platform is way more powerful The state of art has evolved
And let it rest… There will have no Polymer 4…
So Polymer as we know it is dead… But the Polymer Project is indeed alive!
But I have invested so much on it! What to do?
That’s why web components are top You can keep using all your Polymer components and create the new ones with a new library… And it simply works!
Born from the Polymer team For the new web paradigm
Modern lightweight web components For the new web paradigm
Based on lit-html An efficient, expressive, extensible HTML templating library for JavaScript
Do you know tagged templates?
function uppercaseExpression(strings, …expressionValues) { var finalString = ” for ( let i = 0; i < strings.length; i++ ) { if (i > 0) { finalString += expressionValues[i - 1].toUpperCase() } finalString += strings[i] } return finalString } const expressions = [ ‘Sophia Antipolis’, ‘RivieraDev’, ‘Thank you’]; console.log(uppercaseJe suis à ${expression[0]} pour ${expression[1]. $expression[2]!
Little known functionality of template literals
lit-html Templates
let myTemplate = (data) => html<h1>${data.title}</h1> <p>${data.body}</p>;
Lazily rendered Generates a TemplateResult
It’s a bit like JSX, isn’t it? The good sides of JSX… but in the standard!
LitElement import { LitElement, html } from ‘lit-element’; // Create your custom component class CustomGreeting extends LitElement { // Declare properties static get properties() { return { name: { type: String } }; } // Initialize properties constructor() { super(); this.name = ‘World’; } // Define a template render() { return html<p>Hello, ${this.name}!</p>; } } // Register the element with the browser customElements.define(‘custom-greeting’, CustomGreeting);
Lightweight web-components using lit-html
Coding my-lit-counter
Web Components & Frameworks Less “either/or” and more “both/and”
Compatibility is on Web Components side Web Components everywhere, baby!
They are the interoperable alternative Any framework… or no framework at all
You can have a single implementation And it simply works everywhere*
*React don’t fully support them yet Long story made short: use lit-labs/react
When you need interoperability Nothing beats the standard
Angular can generate web components Angular Elements
Vue can generate web components With defineCustomElement()
React can generate web components But it can generate them too
What about Svelte? Let’s look in detail one case
Web Components & Design Systems One of the best cases for Web Components
So, what are Design Systems? And why should I look at them?
A talk for devs by a dev I am not a designer, neither I play one on TV…
The same or different?
Style Guides A document listing the styles, patterns, practices, and principles of a brand design standards
Style Guides Style guides define the applicationʼs look and feel
Style Guide Example: Uber https://brand.uber.com/
Style Guide Example: Medium https://www.behance.net/gallery/7226653/Medium-Brand-Development
Style Guides alone are ambiguous Interpretation needed to adapt the preconisation to the use case
Component Catalogs A component catalog is a repository of components, with one or several implementations, code examples and technical documentation
Component Catalog example: Bootstrap https://getbootstrap.com/
Component Catalog Example: ING’s Lion https://lion-web-components.netlify.app/
Catalogs alone create inconsistency Like using the same LEGO bricks to create very different objects
Design Systems A Design System is like a common visual language for product teams
Design systems A Design System is a set of design standards, documentations, and principles, alongside with the toolkit (UI patterns and code components) to achieve those standards
Design systems
Example: Carbon Design System https://www.carbondesignsystem.com/
Example: Firefox’s Photon Design System https://design.firefox.com/photon/
Example: Material Design https://material.io/
The component catalog The poor relative of the Design System family
Let’s choose a simple example Bootstrap based component catalogs
A long time ago Components defined in HTML, CSS and some jQuery
Then it was AngularJS time… And new reference implementations were needed
But you know the sad story… All UI Bootstrap based catalogs woke up with an obsolete implementation
Worry no more, let’s do Angular! ng-bootstrap to the rescue
But times had changed… In 2017 Angular is only one more in the clique
TM React is the new Big Thing So let’s build React Bootstrap…
Wait, what about Vue? We also need BootstrapVue
OK, I think you see my point…
Most Design System do a choice Either they choose a canonical implementation or they ship and maintain several implementations
Both choices are problematic Shipping only one implementation: Web dev ecosystem changes quickly and almost nobody keeps the same framework for years…
Both choices are problematic Shipping several implementations: You need to maintain all the implementation… and you still miss some others
Incomplete catalogs are problematic People will need to recode the components in their chosen framework… Coherence is not guaranteed!!!
Example: Carbon Design System
Web Components & Design Systems A match made in heaven
Compatibility is on Web Components side Web Components everywhere, baby!
Do you remember AngularJS? And all the code put in the trash bin when Angular arrived…
The pain of switching frameworks? Rewriting once again your code…
The impossibility of sharing UI code? Between apps written with different frameworks
Web Components change that In a clean and standard way
They are the interoperable alternative Any framework… or no framework at all
They are truly everywhere 🚀 🚀 Even in the spaaaaaaaace 🚀
You can have a single implementation And it simply works everywhere
When you need interoperability Nothing beats the standard
But how to do it? Designing, developing and managing a catalog of Web Components
Learning from the best https://lion-web-components.netlify.app/
Learning from the best https://github.com/CleverCloud/clever-components
What kind of components? From little atomic blocs to big smart components, and everything in between
A matter of size and complexity What kind(s) of components you want to build
Build from the bottom and go up Eat your own dog food
And how to choose the atoms? Flexibility and configurability are key
And how to choose the atoms? Encode often used patterns
And what about the molecules? Capitalize on your atoms Keep the flexibility and configurability
Big smart business components Encoding your business logic
Internal or external customers? Who are your target users?
Internal customers need off-the-shelf components A well defined and coherent look-and-feel
External customers need to be able to tweak Theming and customizing components
How to organize the catalog Packages, imports and pragmatism
A single repository Single source of truth for the catalog
Two schools of thought A packet per component or a global one
Two schools of thought Individual versioning vs global one
Driving-up adoption Making devs use your components
Think who are your target users Users of any framework current or future…
They aren’t used to your library And they shouldn’t need to be
Go the extra mile to drive up adoption So they don’t need to do it
Make it easy to use As easy as a HTML tag
Document every composant How to use, inputs/outputs, examples…
Documentation isn’t enough Storybook make adoption easy
Keeping a coherent writing style Write down your guidelines
I18n shouldn’t be an afterthought Prepare everything for internationalization
That’s all, folks! Thank you all!
For almost a decade now, we’ve been hearing about Web Components and their appealing promise of finally basing web development on a true component architecture, promoting reusability, modularization, and encapsulation.
However, it is clear that today, in 2023, this promise is still not entirely fulfilled. Frameworks like React, Angular, and Vue continue to dominate the spotlight while the discourse around Web Components remains almost inaudible. Yet, Web Components are now present in many websites and applications we use every day, without us even noticing. The revolution is indeed underway, albeit rather quietly.
In this lab, we will delve into the current evolution of Web Components, examining in detail the main libraries (Lit, Stencil, Hybrid…) and open-source component catalogs (Material, Lion, OpenUI5, Wired…)
We will explore how different frameworks such as Svelte, Vue, and Angular have integrated and managed Web Components. The session aims to provide a comprehensive overview of strategies for creating reusable, framework-independent web components.
We will also address common challenges, such as compatibility issues and Server Side Rendering (SSR) management, and the best practices and solutions for overcoming these problems.
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