map-schema

map-schema is a Node.js library for validating and normalizing JavaScript objects against a defined schema. Current version 0.3.0 (sporadically updated, last release 2018) provides a chainable API to define fields with type checks, default values, custom normalizers, and validators. It supports validation error collection and is designed for scenarios like package.json normalization. Alternatives like Joi or Yup offer more features but map-schema is simpler for basic use.