chore(data-grid): change isCell function into a type guard and remove unnecessary type assertions

.changeset/silver-bottles-pretend.md

@@ -0,0 +1,6 @@
+---
+"@twilio-paste/data-grid": patch
+"@twilio-paste/core": patch
+---
+
+chore(data-grid): change isCell function into a type guard and remove unnecessary type assertions

packages/paste-core/components/data-grid/src/DataGrid.tsx

@@ -98,15 +98,15 @@ export const DataGrid = React.forwardRef<HTMLTableElement, DataGridProps>(
             // Set the actionable state
             setActionable(true);
 
-            const activeElement = getActiveElement() as HTMLElement;
+            const activeElement = getActiveElement();
             // Only if it's a DataGrid cell
-            if (isCell(activeElement)) {
+            if (activeElement && isCell(activeElement)) {
               // Get the first focusable child
               const firstFocusableElement = getFirstFocusableIn(activeElement);
 
               // If there is a focusable child focus it
               if (firstFocusableElement) {
-                ensureFocus(firstFocusableElement as HTMLElement);
+                ensureFocus(firstFocusableElement);
                 // First shift+tab fix upon entering actionable mode
                 activeElement.tabIndex = actionable ? 0 : -1;
               }

packages/paste-core/components/data-grid/src/utils/cell-management.ts

@@ -38,7 +38,7 @@ export const delayedSetFocusable = (element?: HTMLElement): void => {
  *
  * @returns {boolean}.
  */
-export const isCell = (element: Element): boolean => {
+export const isCell = (element: Element): element is HTMLTableCellElement => {
   return element.tagName === "TD" || element.tagName === "TH";
 };
 
@@ -73,7 +73,7 @@ export const getClosestGridCellFromCurrentFocus = (dataGridId: string): HTMLElem
     return null;
   }
   if (isCell(focusedElement)) {
-    return focusedElement as HTMLElement;
+    return focusedElement;
   }
   return getClosestCellFrom(focusedElement, dataGridId);
 };