mirror of
https://github.com/Alfresco/alfresco-ng2-components.git
synced 2025-05-12 17:04:57 +00:00
8471fe40a5
* move translation to core * select scroll directive * register directive * add infinite scroll directive * clean up component and aditional logic * use waitForAsync over async * update docs * change output emitter name * revert to async * restore default value; * test
67 lines
2.4 KiB
TypeScript
67 lines
2.4 KiB
TypeScript
/*!
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* @license
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* Copyright 2019 Alfresco Software, Ltd.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import { Inject, AfterViewInit, Directive, EventEmitter, OnDestroy, Output } from '@angular/core';
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import { MatSelect, SELECT_ITEM_HEIGHT_EM } from '@angular/material/select';
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import { Subject } from 'rxjs';
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import { takeUntil } from 'rxjs/operators';
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@Directive({
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selector: '[adf-infinite-select-scroll]'
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})
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export class InfiniteSelectScrollDirective implements AfterViewInit, OnDestroy {
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static readonly MAX_ITEMS = 50;
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@Output() scrollEnd = new EventEmitter<Event>();
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private onDestroy$ = new Subject<boolean>();
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private itemHeightToWaitBeforeLoadNext = 0;
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constructor(@Inject(MatSelect) private matSelect: MatSelect) {}
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ngAfterViewInit() {
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this.matSelect.openedChange
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.pipe(takeUntil(this.onDestroy$))
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.subscribe((opened: boolean) => {
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if (opened) {
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this.itemHeightToWaitBeforeLoadNext = (this.getItemHeight() * (InfiniteSelectScrollDirective.MAX_ITEMS / 2));
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this.matSelect.panel.nativeElement.addEventListener('scroll', (event: Event) => this.handleScrollEvent(event));
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}
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});
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}
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ngOnDestroy() {
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this.onDestroy$.next(true);
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this.onDestroy$.complete();
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}
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private handleScrollEvent(event: Event) {
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if (this.isScrollInNextFetchArea(event)) {
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this.scrollEnd.emit(event);
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}
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}
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private isScrollInNextFetchArea(event: Event): boolean {
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const target = event.target as HTMLElement;
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return target.scrollTop >= (target.scrollHeight - target.offsetHeight - this.itemHeightToWaitBeforeLoadNext);
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}
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private getItemHeight(): number {
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return parseFloat(getComputedStyle(this.matSelect.panel.nativeElement).fontSize || '0') * SELECT_ITEM_HEIGHT_EM;
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}
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}
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