Sample
Enforce type-only import/export syntax and module boundary semantics under compilerOptions.verbatimModuleSyntax in TypeScript 5.9.3
sha256:296598dcddee3a2413292e3f97d05ceb6034b6814d99f83ad77bc2bf096af918
PUBLISHED
L3_CONTRACT_PASS
MIT-0
Execution evidence
Declared environment and signed verification runs are separated so you can see exactly what this sample proves.
Evidence basisSigned contract pass
Verification receipts1
Verification levelL3_CONTRACT_PASS
Declared environment
- Execution context
- node
- Operating system
- linux
- Architecture
- x64
- Runtime
- node
- Language
- node
- Package manager
- npm
Verification-run environments
- Execution context
- node 22
- Operating system
- linux alpine · musl
- Architecture
- x64
- Runtime
- node 22
- Language
- javascript
- Package manager
- npm
- Execution
- container · docker
CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-17
Case
- Goal
- Enforce type-only import/export syntax and module boundary semantics under compilerOptions.verbatimModuleSyntax in TypeScript 5.9.3 HOW
- Packages
-
typescript 5.9.3
- Environment
- node
- Created
- 2026-08-17T13:25:23Z
Commonly assumed
TypeScript automatically elides type-only named imports and unused value imports during ECMAScript emit regardless of whether type keywords or verbatimModuleSyntax are configured.
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- When compilerOptions.verbatimModuleSyntax is enabled, importing a type without the type modifier fails type-checking with TS1484, and re-exporting a type without export type fails with TS1205, whereas type-only imports and inline type specifiers compile cleanly and are elided during emit.
- compilerOptions.verbatimModuleSyntax preserves unused value imports verbatim in emitted JavaScript rather than eliding them
- In CommonJS module format, compilerOptions.verbatimModuleSyntax rejects top-level export declarations with TS1287 and ES import declarations with TS1286, requiring import equals require and export equals syntax
- In ECMAScript module format, compilerOptions.verbatimModuleSyntax rejects CommonJS export assignment syntax with TS1203
- Specifying removed legacy options importsNotUsedAsValues or preserveValueImports alongside verbatimModuleSyntax produces configuration diagnostics with TS5102
Files
- NOTES.md
- csx.json
- package-lock.json
- package.json
- src/index.mjs
- test/contract.mjs
Download the source artifact (tar.gz)
Origin Seeder
csx-seed
Verification receipts
- node 22 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-17 · ed25519:d91480838ac982c9