kopia lustrzana https://github.com/shoelace-style/shoelace
91 wiersze
2.3 KiB
TypeScript
91 wiersze
2.3 KiB
TypeScript
import { html } from 'lit';
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import { customElement, property } from 'lit/decorators.js';
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import ShoelaceElement from '../../internal/shoelace-element';
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import { watch } from '../../internal/watch';
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import styles from './resize-observer.styles';
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import type { CSSResultGroup } from 'lit';
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/**
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* @summary The Resize Observer component offers a thin, declarative interface to the [`ResizeObserver API`](https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver).
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*
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* @since 2.0
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* @status stable
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*
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* @slot - One or more elements to watch for resizing.
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*
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* @event {{ entries: ResizeObserverEntry[] }} sl-resize - Emitted when the element is resized.
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*/
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@customElement('sl-resize-observer')
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export default class SlResizeObserver extends ShoelaceElement {
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static styles: CSSResultGroup = styles;
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private resizeObserver: ResizeObserver;
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private observedElements: HTMLElement[] = [];
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/** Disables the observer. */
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@property({ type: Boolean, reflect: true }) disabled = false;
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connectedCallback() {
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super.connectedCallback();
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this.resizeObserver = new ResizeObserver((entries: ResizeObserverEntry[]) => {
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this.emit('sl-resize', { detail: { entries } });
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});
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if (!this.disabled) {
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this.startObserver();
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}
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}
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disconnectedCallback() {
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super.disconnectedCallback();
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this.stopObserver();
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}
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private handleSlotChange() {
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if (!this.disabled) {
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this.startObserver();
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}
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}
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private startObserver() {
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const slot = this.shadowRoot!.querySelector('slot');
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if (slot !== null) {
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const elements = slot.assignedElements({ flatten: true }) as HTMLElement[];
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// Unwatch previous elements
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this.observedElements.forEach(el => this.resizeObserver.unobserve(el));
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this.observedElements = [];
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// Watch new elements
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elements.forEach(el => {
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this.resizeObserver.observe(el);
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this.observedElements.push(el);
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});
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}
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}
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private stopObserver() {
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this.resizeObserver.disconnect();
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}
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@watch('disabled', { waitUntilFirstUpdate: true })
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handleDisabledChange() {
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if (this.disabled) {
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this.stopObserver();
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} else {
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this.startObserver();
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}
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}
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render() {
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return html` <slot @slotchange=${this.handleSlotChange}></slot> `;
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}
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}
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declare global {
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interface HTMLElementTagNameMap {
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'sl-resize-observer': SlResizeObserver;
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}
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}
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