Phase 11. TargetJsrLibrary emit

Field	Value
MEP	MEP-72 §Phases
Status	NOT STARTED
Tracking issue	(pending)
Tracking PR	(pending)
Commit	(pending)

Gate

TestPhase11JsrLibrary in package3/typescript/library/phase11_test.go: subtests emit_jsr_json, emit_mod_ts, source_not_dist_invariant, deno_check, publish_dry_run, golden_corpus. The first synthesises a jsr.json from [ts.publish] and asserts the JSON matches the golden. The second emits a mod.ts re-exporting the user's Mochi package's public surface and asserts the file is valid TypeScript. The third asserts NO dist/ directory is emitted (the source-not-dist invariant). The fourth runs deno check mod.ts against the emitted package and asserts no type errors. The fifth runs deno publish --dry-run and asserts the package surface matches the golden. The sixth runs against three end-to-end Mochi packages.

Lowering decisions

The build target is selected via:

[ts.publish]
target = "jsr-library"
package-name = "@mochi/example"
scope = "mochi"
version = "0.1.0"
registry = "https://jsr.io"
license = "Apache-2.0"
homepage = "https://example.com"
description = "Example Mochi package published to JSR"

The emitter produces:

target/ts/jsr-library/
  jsr.json
  README.md (copied from $MOCHI_PROJECT_ROOT/README.md)
  LICENSE (copied from $MOCHI_PROJECT_ROOT/LICENSE)
  mod.ts       # the source entry, exports the public surface
  *.ts         # any additional source files

JSR's invariant: source .ts only, no dist/, no .d.ts. JSR's server-side build (using the bundled deno toolchain) transpiles and emits .d.ts at publish time. The bridge emits the Mochi-source-equivalent .ts files directly into the target dir; the user uploads them via deno publish.

The synthesised jsr.json carries:

{
  "name": "@mochi/example",
  "version": "0.1.0",
  "license": "Apache-2.0",
  "description": "Example Mochi package published to JSR",
  "exports": {
    ".": "./mod.ts"
  },
  "publish": {
    "include": ["./mod.ts", "./README.md", "./LICENSE"],
    "exclude": ["**/*.test.ts", "**/*.spec.ts"]
  }
}

JSR does NOT use the exports-map's import/require/types conditions (JSR is ESM-only). The exports field is a simple specifier-to-path map.

The bridge runs deno check (or deno lint) against the emitted mod.ts as a pre-publish gate; failures stop the publish.

Compared to TargetNpmLibrary, TargetJsrLibrary is simpler: no dual emit, no .d.ts synthesis (JSR's server does it), no package.json. The phase ships ~40% less Go code than phase 10.

Files changed

File	Purpose
package3/typescript/library/jsr.go	EmitJsrLibrary, RenderJsrJson, EmitModTs
package3/typescript/library/deno_check.go	deno check invocation wrapper
package3/typescript/library/phase11_test.go	TestPhase11JsrLibrary sentinel

Test set

6 subtests as listed in the Gate section.

Cross-references

• Research note 06 §3 JSR publish flow — the source-not-dist invariant rationale.
• Research note 02 §3 Dual registry shipped at once — why JSR is first-class.