A runtime library that validates data against TypeScript interfaces, producing informative error messages when values do not match. It is useful for checking parsed JSON or YAML objects (for example, data received over the network) using generated runtime checker code.
Project status
- Maintenance status: Evidence suggests low ongoing maintenance, with the last recorded upstream push on 2024-04-20, and the most recent published updates shown only up to 2021-10-11. As of 2026-06-09, this looks quiet or in maintenance mode rather than actively evolving.
- Update cadence: Updates appear infrequent historically (multiple versions clustered in 2020-2021, then a long gap), with no new version history shown after 2021 in the provided summaries.
AI summary generated
Recent updates
v1.0.2
Release v1.0.2 was published with no release notes provided. The code diff shows only a version bump in the package metadata, with no functional or behavioral code changes.
v1.0.1
v1.0.1 adds tuple rest-type support (via a new t.rest(...) type) and introduces support for the TypeScript type `unknown`. In addition, the library improves how array types are named in error messages, which changes the wording developers will see when unions fail validation.
BreakingFeaturesv1.0.0
Release v1.0.0 was published, but the publisher did not provide any release notes. No specific changes, fixes, or migration guidance are documented in the provided material.
v0.2.1
Version bump to v0.2.1 with a small runtime change in how strict checking handles extraneous properties for intersection types. Release notes are not provided for this version, so the functional behavior update and the involved internal API signature changes need to be inferred from the code diff.
v0.2.0
v0.2.0 adds runtime support for TypeScript index signatures and improves handling of recursive interface type definitions. The release notes are empty, so the documented change list cannot be used to verify what actually changed. The code changes introduce a new exported symbol, alter interface construction/checking to accommodate index signatures, and add recursion-safe checker generation for named types.
BreakingFeaturesv0.1.13
v0.1.13 introduces a new exported TypeScript helper, `CheckerT<T>`, to enable type-guard style narrowing for the existing `Checker` methods `test` and `strictTest`. The release also updates documentation and tests to demonstrate this casting approach, and bumps several development toolchain dependencies (TypeScript, ts-node, Babel-related packages via the lockfile). Release notes were not provided by the publisher.
Featuresv0.1.12
v0.1.12 contains no release notes. The code changes primarily affect error handling internals by fixing VError's prototype chain, and it also exposes VError and IErrorDetail from the public entrypoint.
Featuresv0.1.11
Release v0.1.11 introduces support for intersection types (A & B), including strict-check behavior across intersected members. The release notes provided by the publisher are missing, so the changes below are inferred only from the actual code diff.
Breakingv0.1.10
Release v0.1.10 introduces additional runtime type checkers for native JavaScript objects. The release notes field is empty, so none of these behavioral additions are described by the publisher.
v0.1.9
Release v0.1.9 was published on 2019-08-29, but the publisher did not provide any release notes. No documented changes, feature additions, fixes, security updates, or migration guidance are available from the release text.