diff options
Diffstat (limited to 'client/src/app/shared/video/infinite-scroller.directive.ts')
-rw-r--r-- | client/src/app/shared/video/infinite-scroller.directive.ts | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/client/src/app/shared/video/infinite-scroller.directive.ts b/client/src/app/shared/video/infinite-scroller.directive.ts new file mode 100644 index 000000000..43e014cbd --- /dev/null +++ b/client/src/app/shared/video/infinite-scroller.directive.ts | |||
@@ -0,0 +1,77 @@ | |||
1 | import { Directive, EventEmitter, Input, OnInit, Output } from '@angular/core' | ||
2 | import 'rxjs/add/operator/distinct' | ||
3 | import 'rxjs/add/operator/startWith' | ||
4 | import { fromEvent } from 'rxjs/observable/fromEvent' | ||
5 | |||
6 | @Directive({ | ||
7 | selector: '[myInfiniteScroller]' | ||
8 | }) | ||
9 | export class InfiniteScrollerDirective implements OnInit { | ||
10 | private static PAGE_VIEW_TOP_MARGIN = 500 | ||
11 | |||
12 | @Input() containerHeight: number | ||
13 | @Input() pageHeight: number | ||
14 | @Input() percentLimit = 70 | ||
15 | @Input() autoLoading = false | ||
16 | |||
17 | @Output() nearOfBottom = new EventEmitter<void>() | ||
18 | @Output() nearOfTop = new EventEmitter<void>() | ||
19 | @Output() pageChanged = new EventEmitter<number>() | ||
20 | |||
21 | private decimalLimit = 0 | ||
22 | private lastCurrentBottom = -1 | ||
23 | private lastCurrentTop = 0 | ||
24 | |||
25 | constructor () { | ||
26 | this.decimalLimit = this.percentLimit / 100 | ||
27 | } | ||
28 | |||
29 | ngOnInit () { | ||
30 | if (this.autoLoading === true) return this.initialize() | ||
31 | } | ||
32 | |||
33 | initialize () { | ||
34 | const scrollObservable = fromEvent(window, 'scroll') | ||
35 | .startWith(true) | ||
36 | .map(() => ({ current: window.scrollY, maximumScroll: document.body.clientHeight - window.innerHeight })) | ||
37 | |||
38 | // Scroll Down | ||
39 | scrollObservable | ||
40 | // Check we scroll down | ||
41 | .filter(({ current }) => { | ||
42 | const res = this.lastCurrentBottom < current | ||
43 | |||
44 | this.lastCurrentBottom = current | ||
45 | return res | ||
46 | }) | ||
47 | .filter(({ current, maximumScroll }) => maximumScroll <= 0 || (current / maximumScroll) > this.decimalLimit) | ||
48 | .debounceTime(200) | ||
49 | .distinct() | ||
50 | .subscribe(() => this.nearOfBottom.emit()) | ||
51 | |||
52 | // Scroll up | ||
53 | scrollObservable | ||
54 | // Check we scroll up | ||
55 | .filter(({ current }) => { | ||
56 | const res = this.lastCurrentTop > current | ||
57 | |||
58 | this.lastCurrentTop = current | ||
59 | return res | ||
60 | }) | ||
61 | .filter(({ current, maximumScroll }) => { | ||
62 | return current !== 0 && (1 - (current / maximumScroll)) > this.decimalLimit | ||
63 | }) | ||
64 | .debounceTime(200) | ||
65 | .distinct() | ||
66 | .subscribe(() => this.nearOfTop.emit()) | ||
67 | |||
68 | // Page change | ||
69 | scrollObservable | ||
70 | .debounceTime(500) | ||
71 | .distinct() | ||
72 | .map(({ current }) => Math.max(1, Math.round((current + InfiniteScrollerDirective.PAGE_VIEW_TOP_MARGIN) / this.pageHeight))) | ||
73 | .distinctUntilChanged() | ||
74 | .subscribe(res => this.pageChanged.emit(res)) | ||
75 | } | ||
76 | |||
77 | } | ||