address comments

src/__tests__/FixedSizeGrid.js

@@ -288,21 +288,44 @@ describe('FixedSizeGrid', () => {
       it('should warn about deprecated overscanCount prop', () => {
         spyOn(console, 'warn');
 
+        const renderer = ReactTestRenderer.create(
+          <FixedSizeGrid {...defaultProps} overscanCount={1} />
+        );
+        expect(console.warn).toHaveBeenCalledTimes(1);
+        expect(console.warn).toHaveBeenLastCalledWith(
+          'The overscanCount prop has been deprecated. ' +
+            'Please use the overscanColumnCount and overscanRowCount props instead.'
+        );
+
+        renderer.update(<FixedSizeGrid {...defaultProps} overscanCount={1} />);
+
+        // But it should only warn once.
+        expect(console.warn).toHaveBeenCalledTimes(1);
+      });
+
+      it('should warn about deprecated overscanRowsCount or overscanColumnsCount prop', () => {
+        spyOn(console, 'warn');
+
         const renderer = ReactTestRenderer.create(
           <FixedSizeGrid
             {...defaultProps}
-            overscanCount={1}
             overscanRowsCount={1}
             overscanColumnsCount={1}
           />
         );
         expect(console.warn).toHaveBeenCalledTimes(1);
         expect(console.warn).toHaveBeenLastCalledWith(
-          'The overscanCount, overscanColumnsCount and overscanRowsCount props have been deprecated. ' +
+          'The overscanColumnsCount and overscanRowsCount props have been deprecated. ' +
             'Please use the overscanColumnCount and overscanRowCount props instead.'
         );
 
-        renderer.update(<FixedSizeGrid {...defaultProps} overscanCount={1} />);
+        renderer.update(
+          <FixedSizeGrid
+            {...defaultProps}
+            overscanRowsCount={1}
+            overscanColumnsCount={1}
+          />
+        );
 
         // But it should only warn once.
         expect(console.warn).toHaveBeenCalledTimes(1);

src/createGridComponent.js

@@ -132,10 +132,12 @@ const defaultItemKey = ({ columnIndex, data, rowIndex }) =>
 // In DEV mode, this Set helps us only log a warning once per component instance.
 // This avoids spamming the console every time a render happens.
 let devWarningsOverscanCount = null;
+let devWarningsOverscanRowsColumnsCount = null;
 let devWarningsTagName = null;
 if (process.env.NODE_ENV !== 'production') {
   if (typeof window !== 'undefined' && typeof window.WeakSet !== 'undefined') {
     devWarningsOverscanCount = new WeakSet();
+    devWarningsOverscanRowsColumnsCount = new WeakSet();
     devWarningsTagName = new WeakSet();
   }
 }
@@ -772,21 +774,35 @@ const validateSharedProps = (
     height,
     innerTagName,
     outerTagName,
+    overscanColumnsCount,
     overscanCount,
+    overscanRowsCount,
     width,
   }: Props<any>,
   { instance }: State
 ): void => {
   if (process.env.NODE_ENV !== 'production') {
+    if (typeof overscanCount === 'number') {
+      if (devWarningsOverscanCount && !devWarningsOverscanCount.has(instance)) {
+        devWarningsOverscanCount.add(instance);
+        console.warn(
+          'The overscanCount prop has been deprecated. ' +
+            'Please use the overscanColumnCount and overscanRowCount props instead.'
+        );
+      }
+    }
+
     if (
-      typeof overscanCount === 'number' ||
       typeof overscanColumnsCount === 'number' ||
       typeof overscanRowsCount === 'number'
     ) {
-      if (devWarningsOverscanCount && !devWarningsOverscanCount.has(instance)) {
-        devWarningsOverscanCount.add(instance);
+      if (
+        devWarningsOverscanRowsColumnsCount &&
+        !devWarningsOverscanRowsColumnsCount.has(instance)
+      ) {
+        devWarningsOverscanRowsColumnsCount.add(instance);
         console.warn(
-          'The overscanCount, overscanColumnsCount and overscanRowsCount props have been deprecated. ' +
+          'The overscanColumnsCount and overscanRowsCount props have been deprecated. ' +
             'Please use the overscanColumnCount and overscanRowCount props instead.'
         );
       }