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1 | import { fromEvent, Observable, Subscription } from 'rxjs' | |
2 | import { distinctUntilChanged, filter, map, share, startWith, throttleTime } from 'rxjs/operators' | |
3 | import { AfterViewChecked, Directive, ElementRef, EventEmitter, Input, OnDestroy, OnInit, Output } from '@angular/core' | |
4 | import { PeerTubeRouterService, RouterSetting } from '@app/core' | |
5 | ||
6 | @Directive({ | |
7 | selector: '[myInfiniteScroller]' | |
8 | }) | |
9 | export class InfiniteScrollerDirective implements OnInit, OnDestroy, AfterViewChecked { | |
10 | @Input() percentLimit = 70 | |
11 | @Input() onItself = false | |
12 | @Input() dataObservable: Observable<any[]> | |
13 | ||
14 | // Add angular state in query params to reuse the routed component | |
15 | @Input() setAngularState: boolean | |
16 | @Input() parentDisabled = false | |
17 | ||
18 | @Output() nearOfBottom = new EventEmitter<void>() | |
19 | ||
20 | private decimalLimit = 0 | |
21 | private lastCurrentBottom = -1 | |
22 | private scrollDownSub: Subscription | |
23 | private container: HTMLElement | |
24 | ||
25 | private checkScroll = false | |
26 | ||
27 | constructor ( | |
28 | private peertubeRouter: PeerTubeRouterService, | |
29 | private el: ElementRef | |
30 | ) { | |
31 | this.decimalLimit = this.percentLimit / 100 | |
32 | } | |
33 | ||
34 | ngAfterViewChecked () { | |
35 | if (this.checkScroll) { | |
36 | this.checkScroll = false | |
37 | ||
38 | // Wait HTML update | |
39 | setTimeout(() => { | |
40 | if (this.hasScroll() === false) this.nearOfBottom.emit() | |
41 | }) | |
42 | } | |
43 | } | |
44 | ||
45 | ngOnInit () { | |
46 | this.initialize() | |
47 | } | |
48 | ||
49 | ngOnDestroy () { | |
50 | if (this.scrollDownSub) this.scrollDownSub.unsubscribe() | |
51 | } | |
52 | ||
53 | initialize () { | |
54 | this.container = this.onItself | |
55 | ? this.el.nativeElement | |
56 | : document.documentElement | |
57 | ||
58 | // Emit the last value | |
59 | const throttleOptions = { leading: true, trailing: true } | |
60 | ||
61 | const scrollableElement = this.onItself ? this.container : window | |
62 | const scrollObservable = fromEvent(scrollableElement, 'scroll') | |
63 | .pipe( | |
64 | startWith(true), | |
65 | throttleTime(200, undefined, throttleOptions), | |
66 | map(() => this.getScrollInfo()), | |
67 | distinctUntilChanged((o1, o2) => o1.current === o2.current), | |
68 | share() | |
69 | ) | |
70 | ||
71 | // Scroll Down | |
72 | this.scrollDownSub = scrollObservable | |
73 | .pipe( | |
74 | filter(({ current }) => this.isScrollingDown(current)), | |
75 | filter(({ current, maximumScroll }) => (current / maximumScroll) > this.decimalLimit) | |
76 | ) | |
77 | .subscribe(() => { | |
78 | if (this.setAngularState && !this.parentDisabled) this.setScrollRouteParams() | |
79 | ||
80 | this.nearOfBottom.emit() | |
81 | }) | |
82 | ||
83 | if (this.dataObservable) { | |
84 | this.dataObservable | |
85 | .pipe(filter(d => d.length !== 0)) | |
86 | .subscribe(() => this.checkScroll = true) | |
87 | } | |
88 | } | |
89 | ||
90 | private getScrollInfo () { | |
91 | return { current: this.container.scrollTop, maximumScroll: this.getMaximumScroll() } | |
92 | } | |
93 | ||
94 | private getMaximumScroll () { | |
95 | const elementHeight = this.onItself ? this.container.clientHeight : window.innerHeight | |
96 | ||
97 | return this.container.scrollHeight - elementHeight | |
98 | } | |
99 | ||
100 | private hasScroll () { | |
101 | return this.getMaximumScroll() > 0 | |
102 | } | |
103 | ||
104 | private isScrollingDown (current: number) { | |
105 | const result = this.lastCurrentBottom < current | |
106 | ||
107 | this.lastCurrentBottom = current | |
108 | return result | |
109 | } | |
110 | ||
111 | private setScrollRouteParams () { | |
112 | this.peertubeRouter.addRouteSetting(RouterSetting.REUSE_COMPONENT) | |
113 | } | |
114 | } |