fix(Button): forward formAction prop for React 19

packages/mui-joy/src/Button/Button.tsx

@@ -486,6 +486,10 @@ Button.propTypes /* remove-proptypes */ = {
     PropTypes.oneOf(['outlined', 'plain', 'soft', 'solid']),
     PropTypes.string,
   ]),
+  /**
+   * Supports React 19 declarative actions (formAction).
+   */
+  formAction: PropTypes.oneOfType([PropTypes.func, PropTypes.string]),
 } as any;
 
 // @ts-ignore internal logic for ToggleButtonGroup

packages/mui-material/src/Button/Button.d.ts

@@ -97,6 +97,7 @@ export interface ButtonOwnProps {
    * @default 'text'
    */
   variant?: OverridableStringUnion<'text' | 'outlined' | 'contained', ButtonPropsVariantOverrides>;
+  formAction?: ((formData: FormData) => void) | string;
 }
 
 export type ButtonTypeMap<

packages/mui-material/src/Button/Button.js

@@ -530,6 +530,7 @@ const Button = React.forwardRef(function Button(inProps, ref) {
     startIcon: startIconProp,
     type,
     variant = 'text',
+    formAction,
     ...other
   } = props;
 
@@ -605,6 +606,7 @@ const Button = React.forwardRef(function Button(inProps, ref) {
       id={loading ? loadingId : idProp}
       {...other}
       classes={classes}
+      formAction={formAction}
     >
       {startIcon}
       {loadingPosition !== 'end' && loader}
@@ -743,6 +745,10 @@ Button.propTypes /* remove-proptypes */ = {
     PropTypes.oneOf(['contained', 'outlined', 'text']),
     PropTypes.string,
   ]),
+  /**
+   * Supports React 19's declarative form actions.
+   */
+  formAction: PropTypes.oneOfType([PropTypes.func, PropTypes.string]),
 };
 
 export default Button;

packages/mui-material/src/Button/Button.test.js

@@ -853,5 +853,15 @@ describe('<Button />', () => {
       );
       expect(screen.getByRole('button')).to.have.class(classes.loadingPositionEnd);
     });
+    it('forwards formAction to the DOM button', () => {
+      const handleAction = jest.fn();
+      render(<Button formAction={handleAction}>Submit</Button>);
+
+      const button = screen.getByRole('button', { name: 'Submit' });
+      expect(button).toHaveAttribute('formaction');
+
+      fireEvent.click(button);
+      expect(handleAction).toHaveBeenCalledWith(expect.any(FormData));
+    });
   });
 });