schema-jtd

JSON Schema and JSON Type Definition transformation utilities (contains the schema2td and td2schema commands).

CLI usage

npx --package @koumoul/schema-jtd schema2td --help

Why

• need help migrating from one format to another ?
• need to make a tool written for one format work with the other at low cost ?
• need create an Open API documentation from your JTDs ?
• need to create code bindings from your schemas ?

JTD or JSON Schema ?

Don't be too fast in chosing one and rejecting the other. JSON schema is good for a self documented API that makes many of its validation rules explicit, JTD is great for non-ambiguous types and generating code bindings.

A possible sequence that includes both:

1. write an API specification including self documented JSON schemas
2. use schema2td to produce JTD equivalents
3. use jtd-codegen to produce code bindings
4. use JTD for fast parsing and serializing at both ends of your API endpoints
5. use a JSON Schema validator to validate the payload with extra rules ignored by JTD

Limitations

• schema2td will reject schemas with ambiguous typing (for example a oneOf with different types)
  • this might be resolved in the future using a vocabulary to resolve ambiguous typing (for example by flagging a oneOf to be ignored)
• td2schema will be missing some semantics
  • this is partially compoensated by mapping some JTD metadata to JSON Schema attributes