viewport-observer: match fix made for loading-indicator (#30883)

* viewport-observer: match fix made for loading-indicator * test fix
ampproject · Oct 27, 2020 · b222642 · b222642
1 parent 467a57a
commit b222642
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Showing 2 changed files with 6 additions and 4 deletions.
diff --git a/src/viewport-observer.js b/src/viewport-observer.js
@@ -40,18 +40,20 @@ export function createViewportObserver(ioCallback, win, threshold) {
 
   // TODO(#30794): See if we can safely remove rootMargin without adversely
   // affecting metrics.
-  const rootMargin = '25%';
 
   // Chrome 81+ supports rootMargin in x-origin iframes via {root: document}
   // but this throws in other browsers.
   try {
     return new win.IntersectionObserver(ioCallback, {
       root,
-      rootMargin,
+      rootMargin: '25%',
       threshold,
     });
   } catch (e) {
-    return new win.IntersectionObserver(ioCallback, {rootMargin, threshold});
+    return new win.IntersectionObserver(ioCallback, {
+      rootMargin: '150px',
+      threshold,
+    });
   }
 }
 

diff --git a/test/unit/test-viewport-observer.js b/test/unit/test-viewport-observer.js
@@ -72,7 +72,7 @@ describes.sandboxed('Viewport Observer', {}, (env) => {
         threshold: undefined,
       });
       expect(ctorSpy).calledWith(noop, {
-        rootMargin: '25%',
+        rootMargin: '150px',
         threshold: undefined,
       });
     });