Issue a warning when referencing a missing property #31
Description
In transformers, when a reference to a missing property is met, undefined is returned.
It would be useful to have a warning, in order to, e.g., catch typos.
const sourcePropName : string | undefined = Object.keys(src).find(e => e == elem);
if (!sourcePropName) {
// TODO: issue a warning "reference to a missing property"
// new Issue(
// IssueType.SEMANTIC,
// `A missing property has been referenced: ${elem} in ${src} (class: ${Object.getPrototypeOf(src).constructor.name})`,
// IssueSeverity.WARNING
// )
return undefined;
}