improvements to amp-list load-more (ampproject#30851)

ed-bird · Dec 10, 2020 · 718f7ce · 718f7ce
1 parent ee2f6fd
commit 718f7ce
Show file tree

Hide file tree

Showing 2 changed files with 13 additions and 8 deletions.
diff --git a/extensions/amp-list/0.1/amp-list.js b/extensions/amp-list/0.1/amp-list.js
@@ -1556,8 +1556,9 @@ export class AmpList extends AMP.BaseElement {
   }
 
   /**
-   * If the bottom of the list is within three viewports of the current
-   * viewport, then load more items.
+   * If the bottom of the list is visible and
+   * within three viewports of the current viewport,
+   * then load more items.
    * @private
    */
   maybeLoadMoreItems_() {
@@ -1570,7 +1571,10 @@ export class AmpList extends AMP.BaseElement {
       .getClientRectAsync(dev().assertElement(endoOfListMarker))
       .then((positionRect) => {
         const viewportHeight = this.viewport_.getHeight();
-        if (3 * viewportHeight > positionRect.bottom) {
+        if (
+          positionRect.bottom > 0 &&
+          3 * viewportHeight > positionRect.bottom
+        ) {
           return this.loadMoreCallback_();
         }
       });

diff --git a/extensions/amp-list/0.1/test/test-amp-list.js b/extensions/amp-list/0.1/test/test-amp-list.js
@@ -466,12 +466,13 @@ describes.repeated(
             });
           });
 
-          it('should resize with viewport', () => {
+          it('should resize with viewport', async () => {
             const resize = env.sandbox.spy(list, 'attemptToFit_');
-            list.layoutCallback().then(() => {
-              list.viewport_.resize_();
-              expect(resize).to.have.been.called;
-            });
+            const itemElement = doc.createElement('div');
+            expectFetchAndRender(DEFAULT_FETCHED_DATA, [itemElement]);
+            await list.layoutCallback();
+            list.viewport_.resize_();
+            expect(resize).to.be.calledOnce;
           });
 
           // TODO(choumx, #14772): Flaky.