intercept save button

const { formProps, saveButtonProps, onFinish } = useForm();

const handleOnFinish = (values) => {
  onFinish({
    ...values,
    extraData: "Some extra data"
  });
};

return (
  <Create saveButtonProps={{
    ...saveButtonProps,
    onClick: handleOnFinish
  }}>
    {/* Your form fields */}
  </Create>
);

const { saveButtonProps } = useForm({
  transformValues: (values) => ({
    ...values,
    extraData: "Some extra data"
  }),
});

return (
  <Create saveButtonProps={saveButtonProps}>
    {/* Your form fields */}
  </Create>
);

import { useForm } from "@refinedev/react-hook-form";
import { Create } from "@refinedev/mui";

const PostCreate: React.FC = () => {
  const {
    saveButtonProps,
    refineCore: { onFinish },
    handleSubmit,
  } = useForm();

  const onSubmit = (data) => {
    onFinish({
      ...data,
      extraData: "Some extra data"
    });
  };

  return (
    <Create
      saveButtonProps={{
        ...saveButtonProps,
        onClick: handleSubmit(onSubmit),
      }}
    >
      {/* Your form fields */}
    </Create>
  );
};

import { SaveButton } from "@refinedev/mui";
import { useForm } from "@refinedev/react-hook-form";

const PostCreate: React.FC = () => {
  const {
    saveButtonProps,
    refineCore: { onFinish },
    handleSubmit,
  } = useForm();

  const handleSave = (e: React.MouseEvent<HTMLButtonElement>) => {
    // Prevent the default form submission
    e.preventDefault();

    // Use handleSubmit to get the form data
    handleSubmit((data) => {
      // Add your custom logic here
      const modifiedData = {
        ...data,
        extraData: "Some extra data"
      };

      // Call onFinish with the modified data
      onFinish(modifiedData);
    })(e);
  };

  return (
    <Create>
      {/* Your form fields */}
      <SaveButton {...saveButtonProps} onClick={handleSave} />
    </Create>
  );
};