Web Components in Easy Mode https://webcomponent.io
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Web Component Base

This is a very minimal base class for creating reactive custom elements easily.

When you extend the WebComponent class for your component, you only have to define the template() and observedAttributes(), and changes in any attribute value will automatically cause the UI to render.

The result is a reactive UI on attribute changes.

Table of Contents

  1. Installation
  2. Usage
  3. Life-Cycle Hooks
    1. onInit - the component is connected to the DOM
    2. onChanges - an attribute value changed

Installation

npm i web-component-base

Usage

In your component class:

// HelloWorld.mjs
import WebComponent from "web-component-base";

export class HelloWorld extends WebComponent {
  name = "World";
  emotion = "excited";

  static get observedAttributes() {
    return ["name", "emotion"];
  }

  get template() {
    return `
        <h1>Hello ${this.name}${this.emotion === "sad" ? ". 😭" : "! 🙌"}</h1>`;
  }
}

customElements.define('hello-world', HelloWorld);

In your HTML page:

<head>
  <script type="module" src="HelloWorld.mjs"></script>
</head>
<body>
  <hello-world name="Ayo" emotion="sad">
  <script>
      const helloWorld = document.querySelector('hello-world');

      setTimeout(() => {
        helloWorld.setAttribute('emotion', 'excited');
      }, 2500)
  </script>
</body>

The result is a reactive UI that updates on attribute changes:

UI showing feeling toward Web Components changing from SAD to EXCITED

Life-Cycle Hooks

Define behavior when certain events in the component's life cycle is triggered by providing hook methods

onInit()

  • gets triggered when the component is connected to the DOM
import WebComponent from "../index.mjs";

class ClickableText extends WebComponent {
  onInit() {
    this.onclick = () => console.log(">>> click!");
  }

  get template() {
    return `<span style="cursor:pointer">Click me!</span>`;
  }
}

onChanges()

  • gets triggered when an attribute value changed
import WebComponent from "../index.mjs";

class ClickableText extends WebComponent {
  onChanges({prev, curr}) {
    console.log('>>> something changed', prev, curr)
  }

  get template() {
    return `<span style="cursor:pointer">Click me!</span>`;
  }
}