fix: dynamic size scroll jumping

wellyshen · May 31, 2021 · 48ab76f · 48ab76f
1 parent a88702c
commit 48ab76f
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diff --git a/.changeset/witty-boxes-mate.md b/.changeset/witty-boxes-mate.md
@@ -0,0 +1,5 @@
+---
+"react-cool-virtual": patch
+---
+
+fix: dynamic size scroll jumping
diff --git a/src/useVirtual.ts b/src/useVirtual.ts
@@ -76,6 +76,7 @@ export default <
   const correctScrollCountRef = useRef(0);
   const rosRef = useRef<Map<Element, ResizeObserver>>(new Map());
   const scrollOffsetRef = useRef(0);
+  const prevMeasureIdxRef = useRef(-1);
   const prevVStopRef = useRef<number>();
   const outerRef = useRef<O>(null);
   const innerRef = useRef<I>(null);
@@ -350,7 +351,7 @@ export default <
               const prevEnd = msData[i - 1]?.end || 0;
 
               if (measuredSize !== size || start !== prevEnd) {
-                if (isScrolling && start < scrollOffset)
+                if (i < prevMeasureIdxRef.current && start < scrollOffset)
                   scrollTo(scrollOffset + measuredSize - size);
 
                 msDataRef.current[i] = getMeasure(i, measuredSize);
@@ -359,6 +360,8 @@ export default <
                 hasDynamicSizeRef.current = true;
               }
 
+              prevMeasureIdxRef.current = i;
+
               rosRef.current.get(target)?.disconnect();
               rosRef.current.set(target, ro);
             }).observe(el);