FromOptions converts slice of option.Option[T] into Elastic[T].

FromPointer converts nil to undefined Elastic[T], or defined one whose internal value is dereferenced t.

FromPointers converts []*T into an Elastic[T], treating nil as None[T], and non-nil as Some[T].

FromUnd converts und.Und[option.Options[T]] into Elastic[T].

FromValues converts []T into an Elastic[T].

Null returns a null Elastic[T].

Undefined returns an undefined Elastic[T].

Elastic[T] is a type that can express undefined | null | T | [](null | T).