form-schema-validation

A schema-based object validation library for JavaScript, currently at version 2.0.1. It provides synchronous and asynchronous (Promise-based) validation, supports custom types, one-of type validation, custom validators, and nested schema definitions. Features include validating required/optional fields, object structure, keys, and custom error messages. It is commonly used for form validation but can validate any object. The library offers a simple API with a Schema class and validate method, and allows control over key validation via the validateKeys flag. It is maintained intermittently with low release cadence.