ttsc fix & ttsc format

ttsc is the standalone TypeScript-Go compiler — see Setup if you haven’t installed it yet.

Two commands for two workflows. Both write changes back to disk.

ttsc fix

npx ttsc fix

Applies every autofix the enabled rules offer — lint and format together — writes results back to disk, then re-runs a no-emit type-check + lint pass.

What it does, in order:

1. Loads tsconfig.json + lint.config.ts.
2. Builds the TypeScript-Go Program.
3. Runs every enabled rule. For each rule with an autofix, the fixer produces edits.
4. Applies non-overlapping edits to source files.
5. Writes the rewritten files to disk.
6. Reloads the Program and re-runs the check.
7. Reports remaining diagnostics (errors that couldn’t be autofixed, type errors the autofix didn’t address).

Exit code: 0 if no remaining diagnostics, non-zero otherwise. Source files stay modified either way — the fixes are real writes.

Recommended flow

npx ttsc fix           # locally, before committing
git add -p
git commit
# CI runs:
npx ttsc --noEmit      # gates on zero remaining errors

ttsc fix is for the local developer loop. CI uses ttsc --noEmit and gates on cleanliness — if a ttsc fix should have been run and wasn’t, CI fails.

What it cannot do

• ttsc fix is a one-shot project pass. It rejects --watch, single-file mode, and --emit.
• It does not attempt to fix type errors (it’s not a type-correction tool).
• For rules without autofixers, it reports the diagnostic and moves on.

ESLint delegation

If your project has an eslint.config.* file and ESLint is installed in node_modules, ttsc fix will:

1. Run the native autofixers first.
2. Spawn ESLint to apply ESLint’s own fixers for rules @ttsc/lint doesn’t natively implement.
3. Reload the Program.
4. Report remaining diagnostics.

Useful during phased migrations from ESLint — keep both engines installed, retire ESLint rules one by one as native equivalents land.

ttsc format

npx ttsc format

Same Wadler-style reflow and quote/semi/trailing-comma rewrite as ttsc fix, without the lint cascade.

Use this when:

• You want to reshape source but not touch any non-format rule.
• You’re comparing the format-only output as a Prettier replacement.
• You want a fast pre-commit pass that doesn’t depend on type-checking.

ttsc format skips the post-write re-check. Exit code is 0 unless the format pass itself errored.

Editor integration

The VSCode extension surfaces format and lint violations live. For format-on-save, configure the extension’s “Format on save” command. ttsc format and ttsc fix are also fine as pre-commit hooks (via husky / lint-staged).

Severity gates

ttsc fix rewrites every rule the file’s severity says is not "off". To temporarily disable all format checks without removing them from lint.config.ts, set format.severity: "off" — documented in detail under Format rules → format.severity.

See also

• Format rules — the format/* rules ttsc format applies.
• Rules — the full rule catalog ttsc fix autofixes from.