Data grid: Take scrollbar into account

CHANGELOG.md

@@ -7,6 +7,7 @@
 
 - Fixed invalid color entry passed to `EuiBadge` color prop ([#4481](https://github.com/elastic/eui/pull/4481))
 - Fixed `EuiCodeBlock` focus-state if content overflows ([#4463]https://github.com/elastic/eui/pull/4463)
+- Fixed issues in `EuiDataGrid` around unnecessary scroll bars and container heights not updating ([#4468](https://github.com/elastic/eui/pull/4468))
 
 ## [`31.5.0`](https://github.com/elastic/eui/tree/v31.5.0)
 

src/components/datagrid/data_grid.tsx

@@ -59,7 +59,7 @@ import {
 import { EuiDataGridCellProps } from './data_grid_cell';
 import { EuiButtonEmpty } from '../button';
 import { keys, htmlIdGenerator } from '../../services';
-import { EuiDataGridBody } from './data_grid_body';
+import { EuiDataGridBody, VIRTUALIZED_CONTAINER_CLASS } from './data_grid_body';
 import { useDataGridColumnSelector } from './column_selector';
 import { useDataGridStyleSelector, startingStyles } from './style_selector';
 import { EuiTablePagination } from '../table/table_pagination';
@@ -297,6 +297,47 @@ function renderPagination(props: EuiDataGridProps, controls: string) {
   );
 }
 
+/**
+ * Returns the size of the cell container minus the scroll bar width.
+ * To do so, this hook is listening for size changes of the container itself,
+ * as well as pagination changes to make sure every update is caught.
+ *
+ * This is necessary because there is no callback/event fired by the browser
+ * indicating the scroll bar state has changed.
+ * @param resizeRef the wrapper element containging the data grid
+ * @param pageSize the currently applied page size
+ */
+function useVirtualizeContainerWidth(
+  resizeRef: HTMLDivElement | null,
+  pageSize: number | undefined
+) {
+  const [virtualizeContainerWidth, setVirtualizeContainerWidth] = useState(0);
+  const virtualizeContainer = resizeRef?.getElementsByClassName(
+    VIRTUALIZED_CONTAINER_CLASS
+  )[0] as HTMLDivElement | null;
+
+  // re-render data grid on size changes
+  useResizeObserver(virtualizeContainer);
+
+  useEffect(() => {
+    if (virtualizeContainer?.clientWidth) {
+      setVirtualizeContainerWidth(virtualizeContainer.clientWidth);
+    }
+  }, [virtualizeContainer?.clientWidth]);
+
+  useEffect(() => {
+    // wait for layout to settle, then measure virtualize container
+    setTimeout(() => {
+      if (virtualizeContainer?.clientWidth) {
+        const containerWidth = virtualizeContainer.clientWidth;
+        setVirtualizeContainerWidth(containerWidth);
+      }
+    }, 100);
+  }, [pageSize, virtualizeContainer]);
+
+  return virtualizeContainerWidth;
+}
+
 function useDefaultColumnWidth(
   gridWidth: number,
   leadingControlColumns: EuiDataGridControlColumn[],
@@ -730,6 +771,11 @@ export const EuiDataGrid: FunctionComponent<EuiDataGridProps> = (props) => {
     }
   }, [resizeRef, gridDimensions]);
 
+  const virtualizeContainerWidth = useVirtualizeContainerWidth(
+    resizeRef,
+    pagination?.pageSize
+  );
+
   const hasRoomForGridControls = IS_JEST_ENVIRONMENT
     ? true
     : gridWidth > minSizeForControls || isFullScreen;
@@ -801,7 +847,9 @@ export const EuiDataGrid: FunctionComponent<EuiDataGridProps> = (props) => {
 
   // compute the default column width from the container's clientWidth and count of visible columns
   const defaultColumnWidth = useDefaultColumnWidth(
-    gridDimensions.width,
+    // use clientWidth of the virtualization container to take scroll bar into account
+    // if that's not possible fall back to the size of the wrapper element
+    virtualizeContainerWidth || gridDimensions.width,
     leadingControlColumns,
     trailingControlColumns,
     orderedVisibleColumns

src/components/datagrid/data_grid_body.tsx

@@ -91,6 +91,8 @@ export interface EuiDataGridBodyProps {
   toolbarHeight: number;
 }
 
+export const VIRTUALIZED_CONTAINER_CLASS = 'euiDataGrid__virtualized';
+
 const defaultComparator: NonNullable<
   EuiDataGridSchemaDetector['comparator']
 > = (a, b, direction) => {
@@ -290,7 +292,7 @@ const InnerElement: VariableSizeGridProps['innerElementType'] = forwardRef<
 InnerElement.displayName = 'EuiDataGridInnerElement';
 
 const INITIAL_ROW_HEIGHT = 34;
-const SCROLLBAR_HEIGHT = 15;
+const SCROLLBAR_HEIGHT = 16;
 const IS_JEST_ENVIRONMENT = global.hasOwnProperty('_isJest');
 
 export const EuiDataGridBody: FunctionComponent<EuiDataGridBodyProps> = (
@@ -524,10 +526,10 @@ export const EuiDataGridBody: FunctionComponent<EuiDataGridBodyProps> = (
   const [height, setHeight] = useState<number | undefined>(undefined);
   const [width, setWidth] = useState<number | undefined>(undefined);
 
-  // reset height constraint when rowCount changes
+  // reset height constraint when rowCount or fullscreen setting changes
   useEffect(() => {
     setHeight(undefined);
-  }, [rowCount]);
+  }, [rowCount, isFullScreen]);
 
   const wrapperRef = useRef<HTMLDivElement | null>(null);
   const wrapperDimensions = useResizeObserver(wrapperRef.current);
@@ -584,7 +586,7 @@ export const EuiDataGridBody: FunctionComponent<EuiDataGridBodyProps> = (
               <Grid
                 ref={gridRef}
                 innerElementType={InnerElement}
-                className="euiDataGrid__virtualized"
+                className={VIRTUALIZED_CONTAINER_CLASS}
                 columnCount={
                   leadingControlColumns.length +
                   columns.length +