Add a way to toggle scrollToBottom so you can start scroll from the t…

…op as well and continue reading

See `?continue=top` in matrix-org/matrix-viewer#114 for how this is used

doc/SDK.md

@@ -89,7 +89,7 @@ async function main() {
             navigation,
         });
         await vm.load();
-        const view = new TimelineView(vm.timelineViewModel, viewClassForTile);
+        const view = new TimelineView(vm.timelineViewModel, { viewClassForTile });
         app.appendChild(view.mount());
     }
 }

src/platform/web/ui/session/room/RoomView.js

@@ -70,7 +70,7 @@ export class RoomView extends TemplateView {
                 )]),
                 t.mapView(vm => vm.timelineViewModel, timelineViewModel => {
                     return timelineViewModel ?
-                        new TimelineView(timelineViewModel, this._viewClassForTile) :
+                        new TimelineView(timelineViewModel, { viewClassForTile: this._viewClassForTile }) :
                         new TimelineLoadingView(vm);    // vm is just needed for i18n
                 }),
                 t.mapView(vm => vm.composerViewModel,

src/platform/web/ui/session/room/TimelineView.ts

@@ -57,16 +57,27 @@ function findFirstNodeIndexAtOrBelow(tiles: HTMLElement, top: number, startIndex
     return 0;
 }
 
+interface TimelineViewOpts {
+    viewClassForTile: ViewClassForEntryFn
+    stickToBottom: boolean
+}
 export class TimelineView extends TemplateView<TimelineViewModel> {
 
     private anchoredNode?: HTMLElement;
     private anchoredBottom: number = 0;
     private stickToBottom: boolean = true;
     private tilesView?: TilesListView;
     private resizeObserver?: ResizeObserver;
+    private viewClassForTile: ViewClassForEntryFn;
 
-    constructor(vm: TimelineViewModel, private readonly viewClassForTile: ViewClassForEntryFn) {
+    constructor(vm: TimelineViewModel, {
+        viewClassForTile,
+        stickToBottom = true
+    }: TimelineViewOpts) {
         super(vm);
+
+        this.viewClassForTile = viewClassForTile;
+        this.stickToBottom = stickToBottom;
     }
 
     render(t: Builder<TimelineViewModel>, vm: TimelineViewModel) {