Using LitElement to Build Web Components Interfacing with REST APIs

Web components are modular, reusable UI elements that can be used to create complex user interfaces. They allow developers to create custom elements with HTML, CSS, and JavaScript that can be used across multiple projects. With the advent of modern web frameworks, building web components has become easier than ever.

In this article, we will explore how to use LitElement, a modern JavaScript library, to build web components that interface with REST APIs. LitElement is built on top of the web components standards and provides a simple, yet powerful, way to create web components. It makes it easy to create components that are reactive and fast, making it a great choice for building web components.

Setting up a project with LitElement

Before we dive into building a web component with LitElement, let’s set up a project. You will need to have Node.js and npm installed on your machine.

Step 1. Create a new project directory

mkdir my-component
cd my-component

Step 2. Initialize a new npm project

npm init -y

Step 3. Install LitElement

npm install lit-element

Building a web component

Now that we have set up a project, let’s build a simple web component that retrieves data from a REST API and displays it on the page.

Create a new file my-component.js in your project directory.

Import LitElement

import { LitElement, html } from 'lit-element'; Define a class that extends LitElement

class MyComponent extends LitElement {
  static get properties() {
    return {
      data: { type: Array },
    };
  }

  constructor() {
    super();
    this.data = [];
  }

  async connectedCallback() {
    super.connectedCallback();
    const response = await fetch('https://jsonplaceholder.typicode.com/posts');
    this.data = await response.json();
  }

  render() {
    return html`
      <table>
        <thead>
          <tr>
            <th>ID</th>
            <th>Title</th>
            <th>Body</th>
          </tr>
        </thead>
        <tbody>
          ${this.data.map(
            item => html`
              <tr>
                <td>${item.id}</td>
                <td>${item.title}</td>
                <td>${item.body}</td>
              </tr>
            `
          )}
        </tbody>
      </table>
    `;
  }
}

Summary

In the code above, we have defined a class named MyComponent that extends LitElement. The constructor function sets the initial state of the component by initializing an empty array named data. The connectedCallback function is called when the component is added to the page, and in this function, we fetch data from a REST API using the fetch API. The data is then stored in the data property.

The render function returns the HTML template for the component, and it uses the data property to display the data in a table.