1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
|
import * as debug from 'debug'
import {
AfterViewInit,
ChangeDetectorRef,
ContentChild,
Directive,
ElementRef,
EmbeddedViewRef,
EventEmitter,
OnDestroy,
Output,
TemplateRef,
ViewContainerRef
} from '@angular/core'
const logger = debug('peertube:main:DeferLoadingDirective')
@Directive({
selector: '[myDeferLoading]'
})
export class DeferLoadingDirective implements AfterViewInit, OnDestroy {
@ContentChild(TemplateRef) template: TemplateRef<any>
@Output() loaded: EventEmitter<any> = new EventEmitter()
view: EmbeddedViewRef<any>
private observer: IntersectionObserver
constructor (
private el: ElementRef,
private viewContainer: ViewContainerRef,
private cd: ChangeDetectorRef
) { }
ngAfterViewInit () {
if (this.hasIncompatibleBrowser()) {
return this.load()
}
this.observer = new IntersectionObserver(entries => {
const entry = entries[0]
if (!entry.isIntersecting || entry.target !== this.el.nativeElement) return
this.observer.unobserve(this.el.nativeElement)
this.load()
}, { threshold: 0.1 })
this.observer.observe(this.el.nativeElement)
}
load () {
if (this.isLoaded()) return
logger('Loading component')
this.viewContainer.clear()
this.view = this.viewContainer.createEmbeddedView(this.template, {}, 0)
this.loaded.emit()
this.cd.detectChanges()
}
isLoaded () {
return this.view != null
}
ngOnDestroy () {
this.view = null
if (this.observer) this.observer.disconnect()
}
private hasIncompatibleBrowser () {
return !('IntersectionObserver' in window)
}
}
|
