how to add i18n attribute to custom attribute with object type in angular

Question

I have a component that takes a parameter of type object(errorMessage). One of the property(maximumDate) of that object accepts a static text. I recently started internationalizing the application and not sure how to add i18n attribute for such cases. Did anyone else face a similar situation? any help is appreciated.

<mycomp label="Date of Birth" [errorMessage]="{maximumDate: 'Date of birth can not be future date.'}">
</mycomp>