tsgo-ready

TypeScript 7.0 — the native Go compiler, tsgo — shipped its RC on June 18, 2026, with stable expected about a month later. tsgo --noEmit will tell you if your code still type-checks. It won't tell you that ts-morph can't run on it yet, that your keyofStringsOnly flag is now a hard error, or that the ignoreDeprecations line you added in TS 6 stops working the moment you drop it.

tsgo-ready scans for exactly that — the three things the official check misses:

1. tsconfig flags that are removed in 7.0 (importsNotUsedAsValues, keyofStringsOnly, out, prepend, ...), plus ignoreDeprecations itself (the TS 6 escape hatch that 7.0 deletes) and resolver/target changes.
2. Dependencies that use the Compiler API — ts-morph, ts-patch, ttypescript, typedoc, type-aware typescript-eslint, JSON-schema generators. tsgo ships without a stable programmatic API until 7.1, so these need TypeScript 6 kept alongside. tsgo --noEmit never mentions them.
3. Decorator/metadata and JSDoc surfaces worth a real build before you cut over — NestJS, TypeORM, MikroORM, and const enum under isolatedModules.

Deterministic. No LLM key, no network, no telemetry. It reads your tsconfig.json, package.json, and source files and prints a fix-list.

Run it

npx tsgo-ready

Point it at a directory, or change the output:

npx tsgo-ready --project ./packages/api
npx tsgo-ready --json --out tsgo-report.json
npx tsgo-ready --markdown

What the output looks like

ERROR   Removed compiler option: keyofStringsOnly
   tsconfig.json:8
   `keyofStringsOnly` is deprecated in TypeScript 5/6 and removed in 7.0 — it will
   hard-error. Remove it; `keyof` has included number/symbol keys for years.

WARN    ts-morph uses the TypeScript Compiler API
   package.json
   tsgo ships without the stable programmatic API (planned for 7.1), so ts-morph
   cannot run on tsgo alone yet. Keep TypeScript 6 installed side-by-side.

REVIEW  experimentalDecorators + emitDecoratorMetadata
   tsconfig.json:10
   Build with tsgo and run your tests before cutting over; confirm reflected
   metadata (NestJS/TypeORM-style DI) still resolves.

Summary: 3 error  2 warn  7 review  1 info

Severity

level	meaning
error	will hard-error / stop compiling under tsgo
warn	removed or deprecated surface that very likely needs a change
review	documented behavior change — verify your project, don't assume it breaks
info	minor or context-dependent note

The split matters. The RC notes say code that compiles cleanly under TS 6 (no deprecation warnings silenced) should emit the same under 7.0 — so decorator and const enum findings are review, not error. The tool points you at what to test; it doesn't cry wolf about emit it can't actually verify statically.

In CI

- uses: fernforge/tsgo-ready@main
  with:
    project: .
    fail-on: warn   # error | warn | review | never

It writes a Markdown table to the job summary and fails the step on findings at or above fail-on (default warn). Or call the CLI directly:

- run: npx -y tsgo-ready --fail-on error

Code scanning (Security tab + PR annotations)

Emit SARIF and upload it so each finding shows up inline on the PR and in the repo's Security tab:

- uses: fernforge/tsgo-ready@main
  with:
    fail-on: never        # let the gate happen in code scanning, not the step
    sarif-file: tsgo-ready.sarif
- uses: github/codeql-action/upload-sarif@v3
  if: always()
  with:
    sarif_file: tsgo-ready.sarif

error/warn map to SARIF error/warning; review/info map to note. Each result is anchored to the offending tsconfig.json line, package.json, or source file.

Options

-p, --project <dir>    directory to scan (default: ".")
    --tsconfig <path>  explicit tsconfig (default: auto-discover)
    --format <fmt>     console | json | markdown | sarif
    --json             shorthand for --format json
    --markdown         shorthand for --format markdown
    --sarif            shorthand for --format sarif (GitHub code scanning)
    --out <file>       write the report to a file
    --no-source        skip the source-file walk (config + deps only)
    --no-color         disable ANSI colors
    --fail-on <sev>    error | warn | review | never (default: warn)

Scope and limits

This is a static heuristic scan over config, dependency names, and source patterns. It does not run the compiler. The rule set tracks the documented 6→7 changes — removed options, the Compiler-API gap, the decorator/JSDoc deltas in the typescript-go CHANGES file — and the migration mechanics will keep moving as 7.0 reaches stable and 7.1 restores the programmatic API. Treat the report as a checklist to confirm, then run tsgo --noEmit and your test suite.

Sources behind every rule link to the TypeScript 7.0 RC announcement, the 6.0 announcement, and the typescript-go CHANGES.

MIT.