Extract constant

src/vs/workbench/contrib/files/browser/views/openEditorsView.ts

@@ -244,8 +244,9 @@ export class OpenEditorsView extends ViewletPanel {
 			this.dirtyEditorFocusedContext.reset();
 			const element = e.elements.length ? e.elements[0] : undefined;
 			if (element instanceof OpenEditor) {
-				this.dirtyEditorFocusedContext.set(this.textFileService.isDirty(withNullAsUndefined(element.getResource())));
-				this.resourceContext.set(withUndefinedAsNull(element.getResource()));
+				const resource = element.getResource();
+				this.dirtyEditorFocusedContext.set(this.textFileService.isDirty(resource));
+				this.resourceContext.set(withUndefinedAsNull(resource));
 			} else if (!!element) {
 				this.groupFocusedContext.set(true);
 			}