Web components for design systems and component libraries

Anton Ioffe - October 13th 2023 - 26 minutes read

Embarking on the journey of unraveling the intricacies of Web Components in modern web development can seem like a daunting task. This comprehensive guide is aimed at providing you, a seasoned web developer, with a holistic understanding of web components as powerful tools in design systems and component libraries. You'll explore the depth and breadth of web components, uncover common misconceptions and errors, gain insight into efficient usage practices, and examine existing component libraries and frameworks.

The discourse will take you through an analytical comparison of Web Components and popular JavaScript frameworks, exploring aspects, such as performance, memory and reusability, and highlighting the pragmatic application of Web Components in modern web development. The navigation of the enigmatic Shadow DOM, critical in unlocking the power of Web Components, will illuminate its benefits and limitations.

This exploration aims to equip you with the knowledge and insight to leverage the full potential of Web Components in your development projects. From the theoretical to the practical, this guide endeavors to be a lighthouse in the perpetual evolution of web development. No stone is left unturned, promising a comprehensive package of insights, advice, and best practices. Get ready to delve deep and come out on the other side, an enlightened master of Web Components.

Unraveling the Basics of Web Components in Modern Web Development

Web Components are the cornerstone of design systems and extensive component libraries, revolutionizing how developers conjure immersive web experiences. However, to truly harness their capabilities, a foundational understanding of Web Components is pivotal.

In essence, Web Components are a suite of standardized browser APIs. Despite their simplicity at first glance, they harbour the capability to manifest complex and interactive web experiences. These APIs are built around ever-evolving standards making them a continuously nurturing field in web development.

Why Web Components?

Web Components bring a fresh perspective to the modern web development landscape. Here are some of their distinct advantages:

Platform and Framework Agnosticism

Web Components introduce platform and framework neutrality. With this, you can use a single Web Component across myriad tech stacks and projects within your organization. This unprecedented flexibility promotes consistency and broadens developmental choices.

Imagine the need to render a button on different pages of your web application. Here's a simple button declaration:

class ButtonElement extends HTMLElement{
        this.innerHTML = `<button>Click Me!</button>`;
customElements.define('click-button', ButtonElement);

This button can be summoned anywhere in your application, irrespective of the technology stack or the platform in use, using <click-button></click-button>


Web Components are native to the web, making them infiltrators across a myriad of web ecosystems. In essence, they'll integrate seamlessly irrespective of whether it's a WordPress plugin, a React application or a basic static webpage.

For instance, while working with React, you can import the custom element as follows:

import React from 'react';
import './ButtonElement.js';

function App(){

With this simple import, our custom element is at the disposal of the React ecosystem.


Web Components embody the DRY (Don't Repeat Yourself) principle, facilitating bundling of functionality or design into reusable components, eliminating redundancy.

Understanding the Role of Web Components

In Design Systems

Web Components excel in design systems. HTML, CSS, and presentational JavaScript converge to form high-quality user experiences. Here, the versatile functionality of Web Components minimizes the repetitive tasks commonly associated with frontend development across various tech stacks.

Consider a NavBar component needed across your website:

class NavBar extends HTMLElement {  
  connectedCallback() {
    this.innerHTML = `
        <a href="#">Home</a>
        <a href="#">About</a>
customElements.define('nav-bar', NavBar);

Regardless of how many pages your website has or the diversity of tech stacks employed, you can render the navigation bar on any page using <nav-bar></nav-bar>.

In Component Libraries

Web Components might come across as simple, however, they masterfully handle presentational aspects for a component. They particularly stand out when incorporated within an efficient design system framework.

Consider this custom dropdown component:

class DropDown extends HTMLElement {  
  connectedCallback() {
    this.innerHTML = `
        <option value="">Select</option>
        <option value="opt1">Option 1</option>
        <option value="opt2">Option 2</option>
customElements.define('drop-down', DropDown);

This dropdown component can be used across any framework, for instance React or Vue, and be made functional using the framework's specific logic.

import React, {useState} from 'react';
import './DropDown.js';

function App(){
    const [selectedOption, setSelectedOption] = useState('');
        <drop-down value={selectedOption} onChange={e => setSelectedOption(e.target.value)}></drop-down>

The Catch With Web Components

Web Components aren't invincible. They come with their share of challenges. A few examples include lack of server-side rendering and progressive enhancement support. Some older clients may also run into compatibility issues. Fortunately, these obstacles can be overcome with the tools and resources provided by the rapidly expanding open-source community.

Moreover, not every UI element warrants a Web Component implementation. For less complex elements such as a simple button, standard HTML might suffice rather than a fully-fledged Web Component.

<button style="background: blue; color: white;">Blue Button</button>

In a nutshell, Web Components shine in their ability to blend portability with adaptability. Developers can write code once and deploy it across numerous projects and tech stacks. They are, however, not a panacea. Thoughtful introspection on when and where to apply them can steer the developmental process towards efficiency.

Common Mistakes in Web Components and How to Correct Them

Creating Web Components Unnecessarily

One common mistake that developers often make is creating Web Components without any real need. This usually arises due to the current trend of using Web Components. However, keep in mind that simple UI entities like a standard button or a card may not need to be incorporated into Web Components.

Pros: Using Web Components for basic functionalities might seem like an excellent way to keep everything crossed platforms and frameworks.

Cons: But, creating unnecessary Web Components can turn your codebase complex and difficult to maintain, as you would end up wrapping basic HTML elements.

For instance, observe the unwarranted creation of a button web component:

// Defining a web component for a button
class ButtonComponent extends HTMLElement {
    constructor() {
    connectedCallback() {
        this.innerHTML = `<button id='blue-button'>Click Me</button>`;

customElements.define('button-component', ButtonComponent);

A better, simpler and easy-to-maintain approach is to use standard HTML.

<!-- Standard HTML for a button -->
<button id='blue-button'>Click Me</button>

Handling Business Logic in Web Components

Web Components can be complex entities and are capable of handling various functionalities. However, it's advisable to limit their role in handling only the presentation of components, while the business logic should be managed by JavaScript libraries or frameworks.

Pros: Mixing business logic with presentation in Web Components might seem beneficial for small applications as it reduces the number of files and codes.

Cons: But as the project grows, such practices can lead to unmanageable code and make it difficult to trace bugs.

For example, consider the following case where the Web Component is taking care of the business logic:

// The web component is handling business logic here
class CounterComponent extends HTMLElement {
    constructor() {
        this.counter = 0;
    connectedCallback() {
        this.innerHTML = `<button>Click me to increase counter</button>`;
        this.querySelector('button').addEventListener('click', () => this.counter++ );

customElements.define('counter-component', CounterComponent);

Instead, it's better to delegate the responsibility of handling the business logic to the corresponding JavaScript framework. In the case of React:

// Web component for the button
class CounterComponent extends HTMLElement {
    connectedCallback() {
        this.innerHTML = `<button>Click me</button>`;

customElements.define('counter-component', CounterComponent);


// JavaScript class with business logic
class Counter extends React.Component {
    state = { counter: 0 }
    increaseCounter = () => {
        this.setState((prevState) => ({ counter: prevState.counter+1 }))
    render() {
        return <counter-component onClick={increaseCounter}></counter-component>;

Ignoring the Limitations of Web Components

Web components have certain limitations out-of-the-box. For instance, functionalities like server-side rendering and progressive enhancement aren't supported by default. Also, passing properties to components can be a bit challenging. These are further compounded by the possibility of your application being accessed by outdated clients who don't support the latest Web Component standards.

Pros: Using Web Components alone can make your code cleaner and easier to understand, as they are based on standardized low-level APIs.

Cons: The flip side, however, is that some features may not be available by default and backward compatibility can be a problem.

To demonstrate, let's consider a scenario where a developer attempts to pass a property to a component:

// Passing attributes without a prop definition
class CustomComponent extends HTMLElement {
    connectedCallback() {
        this.innerHTML = `<p>${this.getAttribute('prop')}</p>`;

customElements.define('custom-component', CustomComponent);


<!-- Passing the prop to the component -->
<custom-component prop='This is my prop'></custom-component>

The better and recommended approach is to define a setter and getter for your properties, and track changes using observedAttributes which is a static getter that returns an array of attribute names to be observed for changes.

Note: observedAttributes is a built-in method that lets the Custom Element react to attribute changes. By listing attribute names in the method's return array, we instruct the browser to listen for changes on these attributes and run the attributeChangedCallback method if a change is detected.

// Passing properties with a defined setter and getter
class CustomComponent extends HTMLElement {
    static get observedAttributes() {
        return ['prop'];
    get prop() {
        return this.getAttribute('prop');
    set prop(value) {
        this.setAttribute('prop', value);
    connectedCallback() {
    attributeChangedCallback() {

    render() {
        this.innerHTML = `<p>${this.prop}</p>`;

customElements.define('custom-component', CustomComponent);

Does your development routine echo these common Web Components mistakes? Remember, the objective of using Web Components is to elevate your web development efficiency, and not just for the sake of keeping up with trends.

Deciphering Composition Primitives in Web Components

One of the foundational building blocks in creating Web Components is the utilization of composition primitives. They offer a lower-level approach when compared to other structures, diving deeper beneath the layers of unstyled components. The best reference for understanding composition primitives usage in Web Components is fast-foundation. It provides the tools necessary to compose primitives and create accessible Web Components.

Fast-foundation clients can use these building blocks to build their own design systems and component libraries. It's a lower-level abstraction size compared to fast-components.

import { FoundationElement } from "@microsoft/fast-foundation";

export class MyElement extends FoundationElement {
  /* define your element's API here */

In this sample, a new Web Component is being created by extending the FoundationElement.

Composition Primitives in Web Components

The allure of composition primitives lies in their versatility. They can be combined to build a wide variety of components. For example, the @microsoft/fast-foundation library provides not only the primitive building blocks but also a considerable amount of ready-to-use components. These are well-suited for assembling your own unique component sets, that match your design tokens.

import { 
} from '@microsoft/fast-components';


In this code snippet, fastButton, fastCard, fastDialog are readily-used components from fast-foundation. Integrating these pre-ready components into your project is as easy as calling their respective functions.

This flexibility offers developers an ample room for customization, allowing for unique and individual design components that can easily be built and integrated into any system.

Downsides to Composition Primitives in Web Components

While the usage of composition primitives grants greater control and flexibility, it does come with drawbacks. They require a developer to possess a deeper understanding of Web Components. They are also typically more complex to implement than 'higher-level' options, as this approach demands more intricate coding.

Many developers often fall into a common mistake - using low-level primitives for simple, high-level components where a simpler method could be adopted. This overcomplicating not only adds unnecessary complexity to the code but it also may lead to a performance hit as it takes more processing time.

import { fastButton } from '@microsoft/fast-components';


// codes for handling button events
// which could easily be handled with a high-level component

Using composition primitives aptly revolves around understanding the task at hand. For simple design components, utilizing pre-styled components might serve the purpose more efficiently in comparison to building components from scratch using composition primitives.

Parting Thoughts

Understanding fast-foundation and its use of composition primitives is crucial for developers keen on working with Web Components. The ability to construct powerful, custom elements comes with its share of complexity and difficulties, but the potential benefits it can bring to the overall design system and components library are unparalleled.

Notwithstanding the challenges and learning curve, composition primitives offer a robust solution to the challenge of constructing unique, effective Web Components. Once their principles are firmly grasped, the ease of fabricating flexible and customizable components will be a useful tool in the toolkit of any modern web developer. Thus, a key question we need to ponder upon is - Are we ready to invest the effort in understanding composition primitives fully, to reap their abundant rewards in our Web Component endeavours?

Web Components vs. JavaScript Frameworks - A Comparative Study

Comparing Web Components and JavaScript Frameworks

The ongoing discourse often positions 'Web Components vs JavaScript Frameworks' as two competing ideologies. However, it's crucial to underline that these two are not adversaries but allies in strengthening our web development arsenal. Web components can seamlessly integrate with prevalent JavaScript frameworks like React, Angular, Vue, thereby enhancing their capabilities, rather than trying to usurp them. This synergistic approach fosters a clear separation of concerns, leading to a healthier division of labor.

The Flexibility Advantage

Web Components standout due to their flexibility to harmonize the rich array of JavaScript frameworks. Their inherent compatibility across diverse platforms, coupled with their ability to offload a more significant chunk of operations to the browser, leads to notable performance benefits.

Furthermore, Web Components remain agnostic to any specific framework, granting superior customizability irrespective of whether the deployment is for desktop, mobile, or web applications. This degree of neutrality insulates development teams from the perpetually changing landscape of the JavaScript environment.

Assessing Performance

Web Components excel in optimizing the performance landscape. They significantly reduce the code footprint, proving to be a vital asset for Progressive Web Applications (PWA) deploying on slower networks. Although JavaScript frameworks provide a robust architecture for building intricate applications, they occasionally lag in delivering the lean code structure that is a hallmark of web components.

However, it's crucial to note that web components alone cannot achieve top-tier speed benchmarks for web applications. This is where tools like Stencil take the center stage, extracting essential performance-boosting characteristics from traditional frameworks, and repurposing them for Web Components, thereby amplifying the performance quotient.

Evaluating Adaptability

When we dive into memory management and complexity, both JavaScript frameworks and Web Components display unique strengths and weaknesses. JavaScript frameworks, rich with complex attributes and high-level functionalities, inevitably exert a significant memory toll. In contrast, Web Components, known for their lightweight footprint, make memory-efficient components but may ratchet up complexity levels when extensive customization comes into play.

Consider these code snippets: A JavaScript framework like React might define a simple clickable button as follows:

import React from 'react';
function App() {
  return (
    <button onClick={() => { alert('Clicked') }}>
     Click me

A Web Component for the same functionality would look something like this:

class MyButton extends HTMLElement {
  connectedCallback() {
    this.innerHTML = `<button>Click Me</button>`;
    this.addEventListener('click', _ => alert('Button Clicked'));
customElements.define('my-button', MyButton)

There is a clear tradeoff between readability, modularity, and memory footprint in both approaches, and a developer's familiarity with a given framework might bias their perceptions.

On the reusability front, Web Components naturally score higher, with their core design promoting component reuse across multiple platforms and frameworks.

Striking the Balance

The choice between Web Components and JavaScript frameworks largely hinges upon the precise requirements of the project at hand, the team's proficiency in each technology, and the expectations of the project. Both can be strategically deployed to devise a robust tech stack. A nuanced understanding of their individual strengths and potential synergies is key to leveraging their collective benefits.

In conclusion, unlocking the joint potential of Web Components and JavaScript frameworks largely rests upon a well-calibrated assessment of the development team's needs and capabilities. Such an informed amalgamation could shape your future tech strategy, while opening doors to a compelling blend of fluidity and functional dexterity.

Practical Use of Web Components in Design Systems and Component Libraries

Web Components have truly become a keystone technology in the creation of modern design systems and component libraries. They bring together a unique set of attributes like universal compatibility with different frameworks, immense customizability, and versatility across various platforms, positioning them as a prime candidate for these use cases. Let's delve into the practical application of Web Components in the development and management of design systems and component libraries.

Web Components as a Universally Acceptable Solution

Web Components, celebrated for their standardization and native support in all modern browsers, provide a singular approach for crafting user interfaces. This approach guarantees compatibility across heterogeneous projects and tech stacks, making Web Components an unequivocal victor in the race of foundational technologies for building a design system.

The primary allure of Web Components lies in their indifference to specific frameworks. This remarkable aspect grants your development teams the freedom to select their preferred tools and technologies, hence alleviating integration issues and collaboration barriers.

From a practical standpoint, an effective approach could involve the development of a custom component library using a Web Component compiler such as Stencil. You can now utilize this library uniformly across any project within your organization. The fundamental premise here is that Web Components can align front-end development strategies, bridging separate teams working with various technologies.

To illustrate, below is an indicative example of how a simple Web Component could be defined using Stencil.

import { Component, Prop, h } from '@stencil/core';

  tag: 'my-component',
  styleUrl: 'my-component.css',
export class MyComponent {
  @Prop() name: string;

  render() {
    return <div>Hello, {this.name}!</div>;

This component named 'my-component' can now be used universally across any project in your organization, providing a cohesive implementation standard.

Bridging the Divide between Designers and Developers

A critical area where Web Components demonstrate their prowess is in unifying the efforts of designers and developers. Design systems typically involve designers conceptualizing user interface (UI) elements, which are later turned into functional components by developers.

The immense customizability of Web Components makes them an optimal choice for this interface, as developers can design UI components using HTML, CSS, and JavaScript that adhere meticulously to the design guidelines. This mechanism makes achieving and maintaining design systems a more feasible and streamlined task.

Cross-Platform Usability

Web Components possess the intriguing ability to function agnostic of the platform. In practical usage, the UI library of Web Components you create need not be limited to desktop web applications.

Consider deploying a versatile mobile framework, like Ionic, to extend your Web Components library across a wide spectrum of platforms and devices ranging from native iOS and Android apps, web app frameworks, Electron, and beyond.

Web Components and JavaScript Frameworks

Web Components excel at addressing the presentational aspects of a component while being designed with constraints on built-in functionality. This promotes a comprehensive separation of concerns, where JavaScript libraries or frameworks can infuse these otherwise simple components with the necessary dynamic features.

Frameworks like React, Angular, or Vue, hence, can consume these components, imparting business logic while delegating the presentation layer concerns to Web Components.

By integrating Web Components in design systems and component libraries, organizations can streamline their processes and solidify adherence to best practices. Yet, it's vital to keep in mind that team requirements differ, and Web Components provide a robust, versatile solution uniquely suited to such diverse workflows. Thus, adopting Web Components could potentially redefine the trajectory of your design system journey.

Examination of Component Libraries and Frameworks in Web Components

Component libraries are the backbone of component-based architecture in web development. They provide reusable, standardized, and easily maintainable code pieces that save development time and lead to more consistent user interfaces. In this context, Web Components (WCs) have emerged as a promising technology, offering a standardized way of creating custom, reusable HTML elements. Here, we will throughly look into various major players in this field, such as Lit, Stencil, Auro, Bolt, and Carbon Design System.

Lit, Stencil - The Strong Contenders

Lit and Stencil stand out as powerful libraries when dealing with web components. Their value lies in their capability to provide developers with the high level of abstraction needed to handle JavaScript efficiently, yet without veering away from the merits of custom elements.

Lit, previously known as LitElement, is a simple, lightweight library for creating web components. It facilitates reactive, declarative programming, and its components are easy to read, easy to test, and easy to compose. Lit builds web components that are just that—web components, meaning other developers can use them regardless of their choice of framework and tools.

Stencil, on the other hand, offers a richer set of features, essentially acting as a web component compiler. It takes your decorated TypeScript classes and compiles them into standards-compliant web components, optimized for performance. Some believe that Stencil's real strength lies in its tooling and features common in frameworks, such as lazy loading and async rendering.

Auro, Bolt - Focused on Design Consistency

Some libraries focus on design-first components and deliver a consistent user experience. Auro and Bolt are examples of such libraries.

Auro, created by Alaska Airlines, is an eco-system of design, core utilities, and web components designed to reduce design and development efforts, providing mutual benefits for developers and designers alike.

Bolt, another popular library, focuses on providing a set of robust, high-quality components that use web standards as their engine. Bolt's core principles involve a focus on performance, brand consistence, and extensive documentation.

Carbon Design System - An Exemplary Library

Beyond individual libraries, we have the concept of design systems, coupling user interface components with design guidelines. The Carbon Design System by IBM stands out in this category, based on React, Vue, Angular, and with a focus on web components. As a result, Carbon components are available in different flavors depending on the chosen technology, setting a great example for web components' adaptability and versatility.

Web components combined with component libraries positively impact performance, memory, and code complexity. They enhance readability, modularity, and reusability of the components, all of which are vital for best programming practices.

But how does a developer decide which library or framework to use? The answer is it depends on the project's requirements, the team's expertise, and future plans. This is where the flexibility of web components shines, as they are agnostic to the underlying tools and frameworks, making them an attractive option in multi-stack setups.

A word of advice though, libraries and tools are just means to an end. While they’re essential for getting started and maintaining pace, the central focus should be on delivering a consistent, performant user experience. Leveraging web components is a strategy, not just a tooling choice.

One might ask, if web components are so beneficial, why are they not the default choice for all design systems and component libraries? The answer is not straightforward - as it's not just about the technology but how it fits into to the larger picture, including team's proficiency and preference, project's timeline and resources, and organization's expectations and objectives.

In conclusion, the competitive landscape of frameworks and libraries for web components continues to evolve. Developers must keep abreast with the trends and updates, and make a thoughtful and informed decision about tool adoption and application in their projects.

Organizing Web Components - Unstyled vs Styled Components

Web components have been garnering attention in the web development ecosystem due to their flexibility, reusability, and modularity. Given their capabilities, the competing concepts of unstyled and styled components come to mind when organizing them for your design systems and component libraries. This section aims to delve into these concepts, comparing their benefits and trade-offs with an aim to understand their best application areas.

Unstyled Components

Unstyled components represent the raw blocks of component libraries and design systems. These components embrace flexibility; they are void of any specific styling and rely solely on structural composition. This model of web components allows you to apply your custom styles and design tokens, giving you the freedom to quite literally present your components as you desire.

Fast-foundation and Lion are examples of libraries that offer unstyled components for you to build upon. They provide foundational components, or primitives, which you can use to construct higher-level, customizable components to fit seamlessly into your design frameworks.

Pros of Unstyled Components

  • Flexibility: Unstyled components allow for complete freedom in styling, enabling customization to fit the design requirements.
  • Reusability: They provide universally adoptable structural components, which can be reused and restyled across different projects and frameworks.
  • Framework Independent: Given their lack of preset styling, these components can be imported into any framework or tech stack.

Cons of Unstyled Components

  • Increased Design Load: Creating styles from scratch for each component can be time-consuming, especially when developing large scale applications.
  • Complexity and Inconsistency: Without the structure and uniformity of pre-styled components, maintaining consistency across the application can be challenging.

Styled Components

Unlike unstyled components, styled components come with pre-defined styles. Libraries such as Bootstrap or Ionic offer these pre-styled components, easing the burden of designing and styling components from scratch. These components often come with a provided CSS library or in-built styling syntax, which can be customized to some extent to fit design requirements.

Pros of Styled Components

  • Time-Efficient: Pre-styled components drastically reduce the time and efforts put into defining styles for each component.
  • Consistency: By using the same styled components across the application, it assures visual and functional consistency.
  • Usability: The learning curve to use styled components is typically gentler compared to unstyled components, especially for developers with limited design experience.

Cons of Styled Components

  • Limited Customizability: The preset styles offer limited flexibility in terms of customization.
  • Dependency: There may be dependency on a specific framework or technology, limiting their reusability across different tech stacks.
  • Overhead: Unused styles or features could add unnecessary weight to an application, affecting overall performance.

Decision Time: Unstyled or Styled?

So, should you choose unstyled components or styled ones? There isn't a definitive answer, and it largely depends on your project needs and team dynamics.

Opting for unstyled components can be advantageous when you have unique design requirements that deviate from the conventional UI patterns, and you possess the bandwidth to build and maintain unique component styles. On the other hand, styled components are great when you aim for rapid application development with consistent UI and are comfortable with the style offerings of existing libraries.

Reflect on your project's requirements, timelines, and available resources before you choose between styled and unstyled components. Remember, the best choice is the one that complements your team's strength and aligns with your project goals.

Do you have any experiences to share about managing these trade-offs in your projects? How do you strike a balance between the customizability of unstyled components and the convenience of styled components? Be sure to share your thoughts and experiences!

Shadow DOM - The Good, the Bad, and the Ugly

Shadow DOM: A Detailed Examination

Shadow DOM, a key component of web components, elevates component-based web development by offering a myriad of features. Its workings do bring certain challenges along with its strengths.

Shadow DOM: Key Accomplishments and Features

Shadow DOM's primary offering is ensuring component encapsulation, a core requirement of modern web development. This effectively means that a component's HTML structure, CSS rules, and JavaScript behaviors are immune to the influence of external entities. Notably, Shadow DOM's encapsulation guard also safeguards against unintended alterations from third-party widgets and advertisements.

Breaking Down the Shadow DOM

A noteworthy benefit of the Shadow DOM is style encapsulation. When the styles of a component are enclosed within the Shadow DOM, they can't affect the broader webpage nor be influenced by it. An extension of this is the capability for 'scoped styles', which limits the influence of a component's styles to within that component itself.

Let's delve into an illustrative example:

    /* Styles defined here only affect elements inside 'custom-element' */
    button { 
        background-color: red;
    <slot name="elementButton">
        /* Slots permit flexible content placement */
        <button>Click Me!</button>

This snippet showcases how a button's style is exclusive within the 'custom-element'. Also, the slot named "elementButton" allows content insertion at different instances of the same component class.

Web components also benefit from the Declarative Shadow DOM, ensuring that necessary content and styles are available upon page load, even if JavaScript hasn't loaded yet.

Challenges with Shadow DOM

Despite its benefits, Shadow DOM’s style encapsulation does have some limitations. For instance, when similar styles are to be repeated across multiple components, these styles must be redeclared for each component due to stringent encapsulation. This can lead to repetitive declarations, bloating the CSS and adding to code complexity.

This JavaScript code sample clarifies the challenge posed by the Shadow DOM:

let demoComponent = document.createElement('demoComponent');
/* A Shadow DOM is attached to the 'demoComponent' */
let shadowRoot = demoComponent.attachShadow({ mode: 'open' });

/* Create and append 'style' element to the Shadow DOM */
let styleElement = document.createElement('style');
styleElement.textContent = `
    p { 
        color: red;

/* Create and append 'p' element to the Shadow DOM */
let paraElement = document.createElement('p');
paraElement.textContent = 'Hello from Shadow DOM!';

This code illustrates how Shadow DOM's encapsulation constrains shared styles among components and necessitates extra steps to render a simple paragraph with a style ID.

Unveiling Declarative Shadow DOM

The Declarative Shadow DOM provides a static snapshot of the Shadow DOM tree available as HTML in the browser's source.

<custom-greeter name='World'>
    <template shadowroot='open'>
        /* Scoped style for <b> element */
        b { 
            color: red; 
        <p>Hello <b>World</b>!</p>

This example demonstrates how necessary content and styles are available on page load with no dependency on JavaScript. However, it's essential to be reminded that these stylesheets and scripts loaded via HTML links or script tags might not work as expected within the Shadow DOM due to the encapsulation. Therefore, developers must pay heed to their usage within the Shadow DOM.

Optimizing Shadow DOM Usage

Finding balance between maintaining encapsulation and ensuring developer productivity is the primary goal in using Shadow DOM. Optimization measures can be applied to the encapsulation approach to offer better code optimization and more scalable styling of HTML elements. Albeit these optimizations, the encapsulation imposed by Shadow DOM will significantly influence your application's architectural decisions.

Understanding the Shadow DOM is fundamental in the landscape of web component-based development. Despite the challenges it presents, overcoming these hurdles can pave the way for a robust, encapsulated, and componentized web development landscape. How can enhancements to Shadow DOM improve your development experience while preserving its fundamental characteristics?

Web Components Best Practices

Web Components, by their very nature, offer powerful capabilities for creating reusable, modular components that can be deployed across multiple applications. However, to unlock their full potential and ensure seamless integration across different technologies, it is crucial to follow best practices.

Opt for a Framework Agnostic Approach

One of the core strengths of Web Components is their ability to work independently of the underlying technology or framework. They neither dictate nor depend on a specific framework like Angular, React, or Vue. This feature provides development teams with the flexibility to choose their preferred tools and technologies for different projects.

Hence, a best practice is to adhere to a framework agnostic approach while creating your Web Components. It also future-proofs your components, shielding them from the frequently fluctuating landscape of JavaScript frameworks and tooling.

Pair With JavaScript Frameworks

While Web Components are 'framework agnostic', they can and should be paired with JavaScript frameworks where necessary. Web Components handle the presentational aspects of a component. By pairing them with a JavaScript framework, you can amplify their capabilities and make them functional.

This approach not only creates a clear separation of concerns but also contributes to a healthy division of labor, leading to more efficient and maintainable code.

Leverage Web Component Compilers

In order to stay abreast with enhanced offerings of Web Components, you may need to supplement their primitive set of standards with additional capabilities. Some limitations that might occur when using vanilla Web Components include lack of server-side rendering, uncatered progressive enhancement, or disadvantages with type support, input bindings, and passing properties.

This is where Web Component compilers like Stencil can come to the rescue. They can aid in overcoming these impediments, enhancing the functionality of your Web Components, and making them more proficient to meet your design objectives.

Consider the Mobility of Web Components

Web Components being native to the web, can traverse to any web-based environment. This could range from a conventional static website or Content Management Systems like Wordpress/Drupal, to advanced applications built on React/Vue/Angular.

This inherent advantage of Web Components should not be overlooked and should be capitalized upon to build reusable components that can work in diverse environments with minimum to no tweaking required.

Plan for Component Distribution and Design System Problems

A widely regarded benefit of Web Components is their ability to solve component distribution and design system problems as offered by shared design systems. Hence, it is crucial to understanding that successful and organized usage of Web Components will inherently address these challenges as well.

Handle Nuances Around Web Component Rendering

Lastly, awareness and the ability to address the nuances around how Web Components are rendered is a crucial facet. While the theory suggests they work seamlessly across varied environments, reality might be more complicated. Therefore, understanding these subtle distinctions can make a significant difference in the practical implementation and efficiency of Web Components.

Following these effective strategies can help you to harness the power of Web Components, creating dynamic and effective design systems and component libraries. By doing so, you can ensure a consistent and top-quality user experience across various platforms and devices.



The article explores the use of Web Components in design systems and component libraries for modern web development. It emphasizes the advantages of Web Components, such as platform and framework agnosticism, portability, and reusability. The article discusses the role of Web Components in design systems and component libraries, highlighting their ability to minimize repetitive tasks and handle presentational aspects for components.

Key takeaways from the article include the importance of understanding the basics of Web Components, the benefits and challenges of using them, and the need to strike a balance between unstyled and styled components. The article also emphasizes the need to leverage Web Component compilers, consider the mobility of Web Components across different platforms, and plan for component distribution and design system problems. Overall, the article serves as a guide for developers looking to harness the full potential of Web Components in their development projects.

Technical Task:

Challenge: Create a Web Component using HTML, CSS, and JavaScript that incorporates reusability and can be used across different tech stacks and platforms. Focus on the design and presentational aspects of the component, keeping in mind the principles of Web Components discussed in the article. Test the component by integrating it into different frameworks or platforms to ensure its compatibility and ease of use.

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