The rule helper can be used to add domain attributes to an HTML element. Domain attributes can be used by domain validators.
The "*" parameter is required.
can be converted to:
The added attributes are used for field validation. The construct iterates over all attributes of a JSON control definition and adds rule attributes depending on whether a rule has been defined for that attribute in the factory definition:
At this time, rule attributes are supported for mandatory, io-format, domain values and numeric values.