Meta types

This package defines a simple vocabulary for describing record structures and operations for bridging values between JSON, TypeScript, and RDF.

This is a type-only package, except for the metatypes helper constructor, which is an identity function.

Motivation

TypeScript applications that use an RDF backing store need a single source of truth that supports the following use cases:

• documention
• mapping to RDF
• mapping from RDF
• mapping to JSON (output marshaling)
• mapping from JSON (input marshaling)
• mapping to TypeScript interfaces
• mapping to JSON Schema (if you're into that sort of thing)

Non-goals:

• validation (arbitrary predicates)
• support dictionaries, which have no corollary in RDF

Optionality

It's tempting to try to support “required” properties, but in practice

1. optionality is always contextual (see “Maybe Not”), and

2. graph databases do not make such guarantees in general. At most, a “validate” operation could report that expectations were violated (though clients would still have to deal with missing values).