Added some edge-case tests to Grid. Batched up some scrollLeft/scrollTop state-updates.

Author: bvaughn

source/Grid/Grid.js

@@ -271,24 +271,22 @@ export default class Grid extends Component {
   componentWillUpdate (nextProps, nextState) {
     if (
       nextProps.columnsCount === 0 &&
-      nextState.scrollLeft !== 0
-    ) {
-      this._setScrollPosition({ scrollLeft: 0 })
-    }
-
-    if (
+      nextState.scrollLeft !== 0 ||
       nextProps.rowsCount === 0 &&
       nextState.scrollTop !== 0
     ) {
-      this._setScrollPosition({ scrollTop: 0 })
-    }
-
-    if (nextProps.scrollLeft !== this.props.scrollLeft) {
-      this._setScrollPosition({ scrollLeft: nextProps.scrollLeft })
-    }
-
-    if (nextProps.scrollTop !== this.props.scrollTop) {
-      this._setScrollPosition({ scrollTop: nextProps.scrollTop })
+      this._setScrollPosition({
+        scrollLeft: 0,
+        scrollTop: 0
+      })
+    } else if (
+      nextProps.scrollLeft !== this.props.scrollLeft ||
+      nextProps.scrollTop !== this.props.scrollTop
+    ) {
+      this._setScrollPosition({
+        scrollLeft: nextProps.scrollLeft,
+        scrollTop: nextProps.scrollTop
+      })
     }
 
     computeCellMetadataAndUpdateScrollOffsetHelper({

source/Grid/Grid.test.js

@@ -138,8 +138,36 @@ describe('Grid', () => {
       expect(grid.state.scrollTop).toEqual(1900)
     })
 
-    // @TODO Test updating with new row + scrollTop, removing row, scrolling, then re-adding row (with same scrollTop)
-    // @TODO Test updating with new row + scrollToIndex, removing row, scrolling, then re-adding row (with same scrollToIndex)
+    it('should scroll to a row and column just added', () => {
+      let grid = render(getMarkup())
+      expect(grid.state.scrollLeft).toEqual(0)
+      expect(grid.state.scrollTop).toEqual(0)
+      grid = render(getMarkup({
+        columnsCount: NUM_COLUMNS + 1,
+        rowsCount: NUM_ROWS + 1,
+        scrollToColumn: NUM_COLUMNS,
+        scrollToRow: NUM_ROWS
+      }))
+      expect(grid.state.scrollLeft).toEqual(2350)
+      expect(grid.state.scrollTop).toEqual(1920)
+    })
+
+    it('should scroll back to a newly-added cell without a change in prop', () => {
+      let grid = render(getMarkup({
+        columnsCount: NUM_COLUMNS,
+        rowsCount: NUM_ROWS,
+        scrollToColumn: NUM_COLUMNS,
+        scrollToRow: NUM_ROWS
+      }))
+      grid = render(getMarkup({
+        columnsCount: NUM_COLUMNS + 1,
+        rowsCount: NUM_ROWS + 1,
+        scrollToColumn: NUM_COLUMNS,
+        scrollToRow: NUM_ROWS
+      }))
+      expect(grid.state.scrollLeft).toEqual(2350)
+      expect(grid.state.scrollTop).toEqual(1920)
+    })
   })
 
   describe('property updates', () => {