fix: isElementOfType Improved type inference (#2099)

I missed the 2nd generic argument when I first wrote this util which
made the `type` property resolve to `string |
React.JSXElementConstructor<any>` in certain cases instead of the actual
type. This should fix that.

resolves #2094

packages/react-hooks/src/ElementUtils.test.tsx

@@ -1,7 +1,12 @@
 import { createElement } from 'react';
-import { Text } from '@adobe/react-spectrum';
+import { ItemElement, Item, Text } from '@deephaven/components';
 import { isElementOfType } from './ElementUtils';
 
+beforeEach(() => {
+ jest.clearAllMocks();
+ expect.hasAssertions();
+});
+
 describe('isElementOfType', () => {
  function MockComponent() {
  return null;
@@ -21,4 +26,16 @@ describe('isElementOfType', () => {
  expect(isElementOfType(element, type)).toBe(expected);
  }
  );
+
+ it('should derive the `type` prop', () => {
+ const element: ItemElement = createElement(Item);
+
+ if (isElementOfType(element, Item)) {
+ // This is a type check that verifies the type guard narrows this to the
+ // `Item` function instead of `string | JSXElementConstructor<any>`. This
+ // proves that #2094 is working as expected. Namely, the compiler will
+ // complain if it thinks `type` could be a string.
+ expect(element.type.name).toEqual(Item.name);
+ }
+ });
 });

packages/react-hooks/src/ElementUtils.ts

@@ -1,4 +1,9 @@
-import { isValidElement, ReactElement, ReactNode } from 'react';
+import {
+ isValidElement,
+ JSXElementConstructor,
+ ReactElement,
+ ReactNode,
+} from 'react';
 import { InferComponentProps } from '@deephaven/utils';
 
 /**
@@ -7,10 +12,13 @@ import { InferComponentProps } from '@deephaven/utils';
  * @param type The type to check against
  * @returns True if the node is a React element of the specified type
  */
-export function isElementOfType<T>(
- node: ReactNode,
- type: T
-): node is ReactElement<InferComponentProps<T>> {
+export function isElementOfType<
+ // eslint-disable-next-line @typescript-eslint/no-explicit-any
+ T extends string | JSXElementConstructor<any> =
+ | string
+ // eslint-disable-next-line @typescript-eslint/no-explicit-any
+ | JSXElementConstructor<any>,
+>(node: ReactNode, type: T): node is ReactElement<InferComponentProps<T>, T> {
  return isValidElement(node) && node.type === type;
 }