Replace current state when changing page

[github/Chocobozzz/PeerTube.git] / client / src / app / shared / video / infinite-scroller.directive.ts

diff --git a/client/src/app/shared/video/infinite-scroller.directive.ts b/client/src/app/shared/video/infinite-scroller.directive.ts
index 16e901c34f1208d7d978ffd9efbf7f6129547e4d..e2730423f38e9fd19d17085e6a3396897ea8b4e8 100644 (file)
--- a/client/src/app/shared/video/infinite-scroller.directive.ts
+++ b/client/src/app/shared/video/infinite-scroller.directive.ts
@@ -1,17 +1,19 @@
-import { Directive, EventEmitter, Input, OnInit, Output } from '@angular/core'
+import { Directive, EventEmitter, Input, OnDestroy, OnInit, Output } from '@angular/core'
 import 'rxjs/add/operator/debounceTime'
 import 'rxjs/add/operator/distinct'
 import 'rxjs/add/operator/distinctUntilChanged'
 import 'rxjs/add/operator/filter'
 import 'rxjs/add/operator/map'
+import 'rxjs/add/operator/share'
 import 'rxjs/add/operator/startWith'
 import 'rxjs/add/operator/throttleTime'
 import { fromEvent } from 'rxjs/observable/fromEvent'
+import { Subscription } from 'rxjs/Subscription'
 
 @Directive({
   selector: '[myInfiniteScroller]'
 })
-export class InfiniteScrollerDirective implements OnInit {
+export class InfiniteScrollerDirective implements OnInit, OnDestroy {
   private static PAGE_VIEW_TOP_MARGIN = 500
 
   @Input() containerHeight: number
@@ -26,6 +28,9 @@ export class InfiniteScrollerDirective implements OnInit {
   private decimalLimit = 0
   private lastCurrentBottom = -1
   private lastCurrentTop = 0
+  private scrollDownSub: Subscription
+  private scrollUpSub: Subscription
+  private pageChangeSub: Subscription
 
   constructor () {
     this.decimalLimit = this.percentLimit / 100
@@ -35,14 +40,25 @@ export class InfiniteScrollerDirective implements OnInit {
     if (this.autoLoading === true) return this.initialize()
   }
 
+  ngOnDestroy () {
+    if (this.scrollDownSub) this.scrollDownSub.unsubscribe()
+    if (this.scrollUpSub) this.scrollUpSub.unsubscribe()
+    if (this.pageChangeSub) this.pageChangeSub.unsubscribe()
+  }
+
   initialize () {
+    // Emit the last value
+    const throttleOptions = { leading: true, trailing: true }
+
     const scrollObservable = fromEvent(window, 'scroll')
       .startWith(true)
-      .throttleTime(200)
+      .throttleTime(200, undefined, throttleOptions)
       .map(() => ({ current: window.scrollY, maximumScroll: document.body.clientHeight - window.innerHeight }))
+      .distinctUntilChanged((o1, o2) => o1.current === o2.current)
+      .share()
 
     // Scroll Down
-    scrollObservable
+    this.scrollDownSub = scrollObservable
       // Check we scroll down
       .filter(({ current }) => {
         const res = this.lastCurrentBottom < current
@@ -51,11 +67,10 @@ export class InfiniteScrollerDirective implements OnInit {
         return res
       })
       .filter(({ current, maximumScroll }) => maximumScroll <= 0 || (current / maximumScroll) > this.decimalLimit)
-      .distinct()
       .subscribe(() => this.nearOfBottom.emit())
 
     // Scroll up
-    scrollObservable
+    this.scrollUpSub = scrollObservable
       // Check we scroll up
       .filter(({ current }) => {
         const res = this.lastCurrentTop > current
@@ -66,15 +81,17 @@ export class InfiniteScrollerDirective implements OnInit {
       .filter(({ current, maximumScroll }) => {
         return current !== 0 && (1 - (current / maximumScroll)) > this.decimalLimit
       })
-      .distinct()
       .subscribe(() => this.nearOfTop.emit())
 
     // Page change
-    scrollObservable
+    this.pageChangeSub = scrollObservable
       .distinct()
-      .map(({ current }) => Math.max(1, Math.round((current + InfiniteScrollerDirective.PAGE_VIEW_TOP_MARGIN) / this.pageHeight)))
+      .map(({ current }) => this.calculateCurrentPage(current))
       .distinctUntilChanged()
       .subscribe(res => this.pageChanged.emit(res))
   }
 
+  private calculateCurrentPage (current: number) {
+    return Math.max(1, Math.round((current + InfiniteScrollerDirective.PAGE_VIEW_TOP_MARGIN) / this.pageHeight))
+  }
 }