WEBDEV-7022 Ensure initial page of results always triggers scroller refresh (#402)

* Ensure initial page of results always triggers scroller refresh

* Add additional logging

* Adds monitor to ensure tile count reflects data size

* Remove log statements

Author: latonv

src/collection-browser.ts

@@ -1424,6 +1424,8 @@ export class CollectionBrowser
       if (oldObserver) this.disconnectResizeObserver(oldObserver);
       this.setupResizeObserver();
     }
+
+    this.ensureAvailableTilesDisplayed();
   }
 
   connectedCallback(): void {
@@ -1461,6 +1463,24 @@ export class CollectionBrowser
     this.updateLeftColumnHeight();
   }
 
+  /**
+   * Ensures that if we have new results from the data source that are not yet
+   * displayed in the infinite scroller, that they are immediately reflected
+   * in the tile count.
+   */
+  private ensureAvailableTilesDisplayed(): void {
+    if (
+      this.infiniteScroller &&
+      this.infiniteScroller.itemCount < this.dataSource.size
+    ) {
+      this.setTileCount(
+        this.dataSource.endOfDataReached
+          ? this.dataSource.size
+          : this.estimatedTileCount
+      );
+    }
+  }
+
   /**
    * Updates the data source with the current state of facet readiness for loading,
    * so that they will begin to load in at the appropriate time according to the

src/data-source/collection-browser-data-source.ts

@@ -1120,19 +1120,21 @@ export class CollectionBrowserDataSource
 
       // Update the data source for each returned page.
       // For loans and web archives, we must account for receiving more pages than we asked for.
-      if (
-        this.host.profileElement === 'lending' ||
-        this.host.profileElement === 'web_archives'
-      ) {
+      const isUnpagedElement = ['lending', 'web_archives'].includes(
+        this.host.profileElement!
+      );
+      if (isUnpagedElement) {
         numPages = Math.ceil(results.length / this.pageSize);
         this.endOfDataReached = true;
         if (this.activeOnHost) this.host.setTileCount(this.totalResults);
       }
+
       for (let i = 0; i < numPages; i += 1) {
         const pageStartIndex = this.pageSize * i;
         this.addFetchedResultsToDataSource(
           pageNumber + i,
-          results.slice(pageStartIndex, pageStartIndex + this.pageSize)
+          results.slice(pageStartIndex, pageStartIndex + this.pageSize),
+          !isUnpagedElement || i === numPages - 1
         );
       }
     }
@@ -1157,16 +1159,17 @@ export class CollectionBrowserDataSource
    */
   private addFetchedResultsToDataSource(
     pageNumber: number,
-    results: SearchResult[]
+    results: SearchResult[],
+    needsReload = true
   ): void {
     const tiles: TileModel[] = [];
     results?.forEach(result => {
       if (!result.identifier) return;
       tiles.push(new TileModel(result));
     });
+
     this.addPage(pageNumber, tiles);
-    const visiblePages = this.host.currentVisiblePageNumbers;
-    const needsReload = visiblePages.includes(pageNumber);
+
     if (needsReload) {
       this.refreshVisibleResults();
     }