ts4023-effect-errors

# TS4023 with Effect Error Types ## Problem Exporting function returning `Effect` → TypeScript generates `.d.ts` → error types in Effect's error channel not exported from source package → TS4023. **TS4023 message is misleading**: mentions internal Effect types (`Channel`, `Sink`, `Stream` from `effect/Cause`), not actual missing errors. ## Solution Export ALL error types that appear in any Effect's error channel - including non-exported `class` definitions. ### 1. Find ALL TaggedError classes (not just exported ones) ```bash # Find Data.TaggedError and Schema.TaggedError (both can appear in Effect error channels) rg "class \w+Error extends (Data|Schema)\.TaggedError" packages/<package-name>/src ``` **Critical**: Include classes WITHOUT `export` keyword. Example: ```typescript // This ALSO needs to be exported if used in any Effect's error channel class EmptyComponentSetError extends Data.TaggedError('EmptyComponentSetError')<{...}> {} ``` ### 2. For non-exported errors, add export to source file first ```typescript // Before class EmptyComponentSetError extends Data.TaggedError('EmptyComponentSetError')<{...}> {} // After export class EmptyComponentSetError extends Data.TaggedError('EmptyComponentSetError')<{...}> {} ``` ### 3. Then export from index.ts ```typescript export type { EmptyComponentSetError } from './core/componentSetService'; ``` ### 4. Verify ```bash npx tsc --build packages/<package-name> --force ``` ## Why non-exported errors matter If a service method like `ensureNonEmptyComponentSet` can fail with `EmptyComponentSetError`, that error type appears in the Effect's error channel. Any exported function calling that method inherits the error in its type signature. TypeScript needs to name it in `.d.ts`. ## Knip false positives Knip flags these as "unused exports" when the error class is defined and used within the same file but exported only for TS4023 reasons. Ignore these warnings - TypeScript needs the exports for declaration emit, not runtime imports. **Errors exported for cross-package consumption** (e.g. re-exported from a service package's `index.ts` and imported by another package) are NOT false positives - knip correctly sees them as used, so leave them as-is. ## Checklist - [ ] `rg "class.*TaggedError"` - find ALL errors (with AND without `export`) - [ ] Add `export` to any non-exported error classes used in Effect chains - [ ] Add `export type { ErrorName }` to services `index.ts` - [ ] `npx tsc --build <package> --force` passes - [ ] Ignore knip "unused" warnings for these exports