experiments with Angular and Web Components
Sketching out hosting Angular Components as Custom Elements / Web Components
Angular Component API (4.x)
Angular components are
//annotate with metadata about template and styles
@Component({
selector: 'my-component',
templateUrl: 'my-component.html',
styleUrls: [ 'my-component.css' ],
viewEncapsulation: ViewEncapsulation.Native //Shadow DOM V0
providers: [ SomeService ],
})
class MyComponent {
//public API for component consumers
@Input() someProperty:any; //property values passed in
@Output() someEvent new EventEmitter(); //events go out
@ViewChild(ChildComponent) childView:ChildComponent;
@ViewChildren(ItemComponent) items:QueryList<ItemComponent>
//bind to host element events
@HostListener('mousemove', ['$event'])
onMouseMouse(event:MouseEvent){}
//bind to host properties and attributes
@HostBinding('attr.aria-foo') someValue;
//lifecycle events
ngOnInit(){}
ngOnChanges(changes){}
ngDoCheck(){}
ngOnDestroy(){}
//view lifecycle events
ngAfterContentInit(){}
ngAfterContentChecked(){}
ngAfterViewInit(){}
ngAfterViewChecked(){}
}
Custom Elements v1 API
class MyCustomElement extends HTMLElement {
//newable
constructor(...optionalArgs?:any[]){}
//attributes to observe changes to
static get observedAttributes():string[]{ return ['value', 'foo'] }
//properties
someProp:string;
set foo(value:string) { }
get foo() { return 'foo' }
//dispatch events
onClick(){
this.dispatchEvent(new CustomEvent('some-event', options))
}
//called when attributes change
attributeChangedCallback(attributeName, oldValue, newValue, namespace):void {}
//called when connected to a document / shadow tree
connectedCallback():void {}
//called when removed from document
disconnectedCallback():void {}
}