Online Stencil playground with real TypeScript decorators, TSX components, scoped styles, events, and browser compilation.
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import './components/counter-card/counter-card'
import './global.css'
document.addEventListener('countChanged', (event) => {
console.log('Stencil event:', (event as CustomEvent<number>).detail)
})
import { Component, Event, EventEmitter, h, Prop, State } from '@stencil/core'
@Component({
tag: 'counter-card',
styleUrl: 'counter-card.css',
shadow: true,
})
export class CounterCard {
@Prop() start = 0
@State() count = 0
@Event() countChanged!: EventEmitter<number>
componentWillLoad() {
this.count = this.start
}
private increment = () => {
this.count += 1
this.countChanged.emit(this.count)
}
render() {
return (
<section class="card">
<div>
<span>Reactive state</span>
<strong>{this.count}</strong>
</div>
<button type="button" onClick={this.increment}>
Increment
</button>
</section>
)
}
}
The editor uses Monaco, the engine behind VS Code, with language-aware editing tools and familiar keyboard controls.
Edit a source file from the project explorer — the live preview recompiles automatically.
Add, rename, duplicate or delete project files as needed. Update affected imports after renaming or moving a file.
Use the console for logs and errors, and Format to tidy the active file.
Share the complete project or download a Stencil CLI project ZIP with its source files and configuration.
Stencil 3.2
TypeScript and TSX
Component Decorators
Reactive State and Props
Shadow DOM Encapsulation
Local File Imports
Auto-run updates the preview as you type. Turn it off to run manually with Run or Ctrl/⌘ + Enter.
The Console prompt can inspect browser globals and the rendered DOM, but not variables scoped inside ES modules or component state.
Console shortcuts apply when its prompt is focused. Editor shortcuts apply inside the code editor.
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