4.0.0

4.0.0 — TS-type, performance, and compiler-strictness pass

A consolidated feat! that tightens the public type surface, hardens error objects at runtime, and makes the library compile cleanly under stricter TS settings. No new features — existing code that uses the factory API and treats IConwayError as read-only will keep working.

Breaking changes

• IConwayError is now fully readonly. rootContext, contextsChunk, feature, originalError, extendedParams, and emit are declared readonly and the constructed instance is Object.freezed. Consumers that mutated these fields post-construction (e.g. reassigning error.feature = "...") will get a TypeError in strict mode at runtime and a TS error at compile time.
• originalError and extendedParams are now T | undefined (always-present, possibly-undefined) instead of optional (?:). This is intentional for compatibility with exactOptionalPropertyTypes: true. Reading them is unchanged; spreading or property-presence checks ("originalError" in err) now always observe the key.
• OriginalError is now unknown. Previously Error | Record<string, unknown> | unknown. Callers passing odd values still work; downstream code that narrowed against the old union must re-narrow.
• isConwayError is now brand-based, not instanceof-based. Errors carry a non-enumerable Symbol.for("conway-errors:brand") property. Cross-realm errors and library-produced errors now both round-trip through isConwayError. Anything that hand-constructed a ConwayError-like object without going through the factory will no longer be recognised.
• package.json#exports uses the nested conditional form ("." subpath with import / require / types). Modern bundlers and Node ESM resolution are unaffected; very old toolchains that did not understand subpath exports may need an update.

Improvements

• Public type exports. EmitFn, ExtendedParams, CreateErrorOptions, ErrorTypeConfig, and ErrorFnOptions are now exported from the package root.
• Stricter publish gate. prepublishOnly now runs type-check before lint/test/build, catching type regressions before they hit the registry.
• Compile-time type tests. A new index.test-d.ts (100 lines) asserts type-level guarantees alongside the runtime test suite.
• Expanded runtime test suite. 28 tests covering branded paths, freeze semantics, brand-based recognition, and message-postfix behaviour.
• Cleaner constructor flow. feature is set in the constructor rather than mutated afterwards — required for the freeze, and removes a footgun where the field briefly held "".

Migration

Most consumers need no changes. If you do any of these, adjust:

1. Mutating error.feature, error.extendedParams, etc. after construction → stop; pass the values through the factory.
2. Relying on error instanceof ConwayError from outside the package → switch to isConwayError(error).
3. Type-narrowing on the old OriginalError union → narrow against unknown instead.
4. exactOptionalPropertyTypes: true users who previously got undefined rejected when assigning to originalError/extendedParams → those slots are now declared T | undefined, so explicit undefined is allowed.

Internals

• Bundle size unchanged (~1.3 kB gzipped main entry).
• Zero runtime dependencies preserved.

3.2.1

What's Changed

• Update README (en/ru). Improve library documentation (ru and en)
• Create more auto tests for improve stability and quality

Full Changelog: 3.2.0...3.2.1

3.2.0

What's Changed

• feat: branded types for context, subcontext and features by @ivklgn in #11

Full Changelog: 3.1.2...3.2.0

Updates

1. Improve types for subcontext and features

  const createErrorContext = createError([{ errorType: "ErrorType1" }, { errorType: "ErrorType2" }] as const);
  // ErrorSubcontext<ContextName, "ErrorType1" | "ErrorType2">

  const errorContext = createErrorContext("Context");
  // ErrorSubcontext<"Context", "ErrorType1" | "ErrorType2">
  
  const featureError = errorContext.feature("Feature");
  // ErrorFeature<"Context/Feature", "ErrorType1" | "ErrorType2">

2. Add new utility type readme

3.1.2

Documentation updates

Full Changelog: 3.1.1...3.1.2

3.1.1

What's Changed

• fix: add feature to base error class as prop by @ivklgn in #10

Full Changelog: 3.1.0...3.1.1

3.1.0

What's Changed

• Fix Readme example by @AlexMubarakshin in #8
• feat: add extended params to error object by @ivklgn in #9

Full Changelog: 3.0.1...3.1.0

3.0.1

What's Changed

• Refactor error handling for emit function in example from README by @AlexMubarakshin in #5
• Fix Readme examples by @AlexMubarakshin in #6
• Add GitHub Actions workflow for linting and testing by @AlexMubarakshin in #7

New Contributors

• @AlexMubarakshin made their first contribution in #5

Full Changelog: 3.0.0...3.0.1

3.0.0

BREAKING CHANGES

• move original error into options object (example: https://github.com/ivklgn/conway-errors/blob/main/index.test.ts#L118)

What's new

• add extendedParams to options of error feature instance (example: https://github.com/ivklgn/conway-errors/blob/main/index.test.ts#L231)

2.0.0

What's Changed

• Separate throw and emit by @alex-knyazev in #2
• feat: do not implement throw function in library, allow client to throw error instance by @alex-knyazev in #4

Full Changelog: 0.1.2...2.0.0

https://www.npmjs.com/package/conway-errors/v/2.0.0

0.1.2

• rename context to subcontext
• fix broken types for base error types
• update documentation