property: PropertyValueSet.fromStringOrError cannot return undefined

[jonaskello]

I guess the reason for having PropertyValueSet.fromStringOrError() is that we can parse a string wihtout causing exceptions. However the typing now only allows the return value of PropertyValueSet which means that the onError function must return PropertyValueSet and thus is is not possible to know from the result if the string did parse or not since the return value is always a valid PropertyValueSet even when the parsing fails.

For example this code does not compile:

const parsed = PropertyValueSet.fromStringOrError(() => undefined, s, Units);

[jonaskello]

It seems PropertyFilter.fromString() is typed differently than PropertyValueSet.fromString(). It can return undefined:

PropertyFIlter

function fromString(filter: string, units: Unit.UnitMap): PropertyFilter | undefined;
function fromStringOrEmpty(filterString: string, units: Unit.UnitMap): PropertyFilter;

PropertyValueSet

export declare function fromString(encodedValueSet: string, units: Unit.UnitMap): PropertyValueSet;
export declare function fromStringOrError(onError: (encodedValueSet: string) => PropertyValueSet, encodedValueSet: string, units: Unit.UnitMap): PropertyValueSet;

I think the API should be as similar as possible between these two.