]>
Commit | Line | Data |
---|---|---|
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 | ||
17 | @Output() nearOfBottom = new EventEmitter<void>() | |
18 | ||
19 | private decimalLimit = 0 | |
20 | private lastCurrentBottom = -1 | |
21 | private scrollDownSub: Subscription | |
22 | private container: HTMLElement | |
23 | ||
24 | private checkScroll = false | |
25 | ||
26 | constructor ( | |
27 | private peertubeRouter: PeerTubeRouterService, | |
28 | private el: ElementRef | |
29 | ) { | |
30 | this.decimalLimit = this.percentLimit / 100 | |
31 | } | |
32 | ||
33 | ngAfterViewChecked () { | |
34 | if (this.checkScroll) { | |
35 | this.checkScroll = false | |
36 | ||
37 | // Wait HTML update | |
38 | setTimeout(() => { | |
39 | if (this.hasScroll() === false) this.nearOfBottom.emit() | |
40 | }) | |
41 | } | |
42 | } | |
43 | ||
44 | ngOnInit () { | |
45 | this.initialize() | |
46 | } | |
47 | ||
48 | ngOnDestroy () { | |
49 | if (this.scrollDownSub) this.scrollDownSub.unsubscribe() | |
50 | } | |
51 | ||
52 | initialize () { | |
53 | this.container = this.onItself | |
54 | ? this.el.nativeElement | |
55 | : document.documentElement | |
56 | ||
57 | // Emit the last value | |
58 | const throttleOptions = { leading: true, trailing: true } | |
59 | ||
60 | const scrollableElement = this.onItself ? this.container : window | |
61 | const scrollObservable = fromEvent(scrollableElement, 'scroll') | |
62 | .pipe( | |
63 | startWith(true), | |
64 | throttleTime(200, undefined, throttleOptions), | |
65 | map(() => this.getScrollInfo()), | |
66 | distinctUntilChanged((o1, o2) => o1.current === o2.current), | |
67 | share() | |
68 | ) | |
69 | ||
70 | // Scroll Down | |
71 | this.scrollDownSub = scrollObservable | |
72 | .pipe( | |
73 | filter(({ current }) => this.isScrollingDown(current)), | |
74 | filter(({ current, maximumScroll }) => (current / maximumScroll) > this.decimalLimit) | |
75 | ) | |
76 | .subscribe(() => { | |
77 | if (this.setAngularState) this.setScrollRouteParams() | |
78 | ||
79 | this.nearOfBottom.emit() | |
80 | }) | |
81 | ||
82 | if (this.dataObservable) { | |
83 | this.dataObservable | |
84 | .pipe(filter(d => d.length !== 0)) | |
85 | .subscribe(() => this.checkScroll = true) | |
86 | } | |
87 | } | |
88 | ||
89 | private getScrollInfo () { | |
90 | return { current: this.container.scrollTop, maximumScroll: this.getMaximumScroll() } | |
91 | } | |
92 | ||
93 | private getMaximumScroll () { | |
94 | const elementHeight = this.onItself ? this.container.clientHeight : window.innerHeight | |
95 | ||
96 | return this.container.scrollHeight - elementHeight | |
97 | } | |
98 | ||
99 | private hasScroll () { | |
100 | return this.getMaximumScroll() > 0 | |
101 | } | |
102 | ||
103 | private isScrollingDown (current: number) { | |
104 | const result = this.lastCurrentBottom < current | |
105 | ||
106 | this.lastCurrentBottom = current | |
107 | return result | |
108 | } | |
109 | ||
110 | private setScrollRouteParams () { | |
111 | this.peertubeRouter.addRouteSetting(RouterSetting.REUSE_COMPONENT) | |
112 | } | |
113 | } |