Vue.js 3.0 Tutorial
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In Vue 3, you can use Web Components (or custom elements) like any other Vue component. However, since Web Components are not Vue components, there might be some differences in how you interact with them. Here is a step-by-step tutorial for interacting with a custom element in Vue 3.
Installation:
Follow the instructions from previous tutorials to install Vue 3 and create a new Vue project.
Creating a Web Component:
For this example, let's say we have a basic custom element (Web Component) defined somewhere else and registered globally. It might look like this:
class MyCustomElement extends HTMLElement {
connectedCallback() {
this.innerHTML = `<button>I'm a custom button!</button>`;
}
}
customElements.define('my-custom-element', MyCustomElement);
This is a very simple Web Component that creates a button. The connectedCallback function is part of the Web Component API, it's called when the element is added to the DOM.
Using the custom element in Vue:
In Vue 3, you can use this custom element just like any other HTML element:
<template> <my-custom-element /> </template>
Passing data to a custom element:
To pass data to the custom element, you can use props like you would with a normal Vue component. However, you have to handle the prop updates yourself in the custom element:
class MyCustomElement extends HTMLElement {
static get observedAttributes() {
return ['my-prop'];
}
attributeChangedCallback(name, oldValue, newValue) {
if (name === 'my-prop') {
// Handle the new value of 'my-prop' here
console.log('my-prop changed to: ', newValue);
}
}
}
customElements.define('my-custom-element', MyCustomElement);
Then in Vue, you can pass the prop like this:
<template>
<my-custom-element :my-prop="someData" />
</template>
<script>
export default {
data() {
return {
someData: 'Hello world!'
};
}
};
</script>
Note that in order to pass non-string data to custom elements (like objects or arrays), you would need to encode your data as a JSON string, as attributes on HTML elements can only be strings.
Listening to events from a custom element:
The custom element can emit events that you can listen to in Vue. Let's modify our custom element to emit an event when the button is clicked:
class MyCustomElement extends HTMLElement {
connectedCallback() {
this.innerHTML = `<button>I'm a custom button!</button>`;
this.querySelector('button').addEventListener('click', () => {
this.dispatchEvent(new CustomEvent('my-event', { detail: 'Button clicked!' }));
});
}
}
customElements.define('my-custom-element', MyCustomElement);
Then in Vue, you can listen to this event like so:
<template>
<my-custom-element @my-event="handleEvent" />
</template>
<script>
export default {
methods: {
handleEvent(event) {
console.log(event.detail);
}
}
};
</script>
This is a basic overview of how to interact with custom elements in Vue 3. It allows you to integrate with Web Components and use them like Vue components, with some caveats.
Vue 3.0 Custom Element Properties and Attributes:
Custom elements can receive properties and attributes for configuration.
Properties can be reactive and participate in Vue's reactivity system.
Example code:
// CustomElementPropertiesAttributes.js
import { createApp } from 'vue';
const app = createApp({
props: ['customProp'],
template: '<div>{{ customProp }}</div>',
});
app.component('custom-element', {
props: ['customProp'],
template: '<div>{{ customProp }}</div>',
});
app.mount('#app');
Interacting with Vue 3.0 Custom Elements:
Communicate with custom elements using properties, events, and methods.
Example code:
// InteractingWithCustomElements.js
const customElement = document.querySelector('custom-element');
customElement.customProp = 'Updated value'; // Setting a property
customElement.dispatchEvent(new CustomEvent('custom-event', { detail: 'Event data' })); // Emitting an event
Vue 3.0 Custom Element Events:
Custom elements can emit and listen to events.
Use dispatchEvent to emit events and addEventListener to listen to events.
Example code:
// CustomElementEvents.js
const customElement = document.querySelector('custom-element');
customElement.addEventListener('custom-event', (event) => {
console.log('Event received with data:', event.detail);
});
customElement.dispatchEvent(new CustomEvent('custom-event', { detail: 'Event data' }));
Vue 3.0 Custom Element Lifecycle Hooks:
Custom elements have lifecycle hooks such as connectedCallback and disconnectedCallback.
Use these hooks to perform actions when the element is attached or detached from the DOM.
Example code:
// CustomElementLifecycleHooks.js
class CustomElement extends HTMLElement {
connectedCallback() {
console.log('Element connected to the DOM');
}
disconnectedCallback() {
console.log('Element disconnected from the DOM');
}
}
customElements.define('custom-element', CustomElement);
Vue 3.0 Custom Element Data Binding:
Use Vue's reactivity system for data binding within custom elements.
Reactive properties can be bound to the template.
Example code:
// CustomElementDataBinding.js
const app = createApp({
data() {
return {
customProp: 'Initial value',
};
},
template: '<div>{{ customProp }}</div>',
});
app.component('custom-element', {
data() {
return {
customProp: 'Initial value',
};
},
template: '<div>{{ customProp }}</div>',
});
app.mount('#app');
Creating and Registering Custom Elements in Vue 3.0:
Use the customElements.define method to register custom elements.
Vue components can be registered as custom elements using app.mount.
Example code:
// CreatingAndRegisteringCustomElements.js
const app = createApp({
template: '<div>Vue component as a custom element</div>',
});
app.component('custom-element', {
template: '<div>Vue component as a custom element</div>',
});
const CustomElement = app.mount('#app').$el;
customElements.define('custom-element', CustomElement);
Vue 3.0 Custom Element Slot Usage:
Use slots within custom elements to allow content insertion.
Example code:
// CustomElementSlotUsage.js
const app = createApp({
template: '<div><slot></slot></div>',
});
app.component('custom-element', {
template: '<div><slot></slot></div>',
});
const CustomElement = app.mount('#app').$el;
customElements.define('custom-element', CustomElement);
Styling Vue 3.0 Custom Elements:
Apply styles to custom elements using scoped styles or global styles.
Use the :host selector for styling the custom element itself.
Example code:
// StylingCustomElements.js
const app = createApp({
template: '<div class="custom-element">Styled custom element</div>',
styles: ['.custom-element { color: blue; }'],
});
app.component('custom-element', {
template: '<div class="custom-element">Styled custom element</div>',
styles: ['.custom-element { color: blue; }'],
});
const CustomElement = app.mount('#app').$el;
customElements.define('custom-element', CustomElement);
Vue 3.0 Custom Element Reactivity:
Vue's reactivity system can be used within custom elements for reactive behavior.
Example code:
// CustomElementReactivity.js
const app = createApp({
data() {
return {
customProp: 'Initial value',
};
},
template: '<div>{{ customProp }}</div>',
});
app.component('custom-element', {
data() {
return {
customProp: 'Initial value',
};
},
template: '<div>{{ customProp }}</div>',
});
const CustomElement = app.mount('#app').$el;
customElements.define('custom-element', CustomElement);
Vue 3.0 Custom Element Testing Strategies:
Test custom elements by creating instances and manipulating their properties.
Use testing libraries like Jest and Vue Test Utils for comprehensive testing.
Example code:
// CustomElementTesting.js
import { mount } from '@vue/test-utils';
const wrapper = mount('custom-element', {
props: {
customProp: 'Test value',
},
});
expect(wrapper.text()).toBe('Test value');
Vue 3.0 Custom Element Composition:
Compose custom elements with other custom elements or Vue components.
Use the is attribute for dynamic component composition.
Example code:
// CustomElementComposition.js
const app = createApp({
template: '<custom-element is="another-custom-element"></custom-element>',
});
app.component('custom-element', {
template: '<div>Parent custom element</div>',
});
app.component('another-custom-element', {
template: '<div>Child custom element</div>',
});
const CustomElement = app.mount('#app').$el;
customElements.define('custom-element', CustomElement);
Examples of Vue 3.0 Custom Element Integration:
Integrate Vue components as custom elements in various scenarios.
Examples may include form elements, data visualization, or complex UI components.
Example code:
// CustomElementIntegrationExample.js
const app = createApp({
template: '<custom-form></custom-form>',
});
app.component('custom-form', {
template: '<form>Vue-powered form</form>',
});
const CustomForm = app.mount('#app').$el;
customElements.define('custom-form', CustomForm);