Compile (ttsc)

Day-to-day compiler commands and the full flag reference.

Build the project


npx ttsc

Reads tsconfig.json from the current directory, type-checks the project, runs every configured plugin, writes JavaScript + declaration files to outDir. Equivalent to ttsc build.

Type-check only


npx ttsc --noEmit
npx ttsc check     # same thing, named subcommand

No files written. Non-zero exit on failure — this is the CI form.

Watch


npx ttsc --watch

Re-compiles on save. Pass --preserveWatchOutput to keep your scrollback.

Other day-to-day commands


npx ttsc -p tsconfig.build.json     # pick a tsconfig
npx ttsc --outDir build/server      # override outDir
npx ttsc --emit                     # force emit when noEmit: true is set
npx ttsc --verbose                  # print every emitted file path
npx ttsc fix                        # apply lint + format autofixes, then re-check
npx ttsc format                     # apply only format autofixes (no lint cascade)
npx ttsc prepare                    # pre-build plugin cache (CI warmup)
npx ttsc clean                      # drop the plugin cache

ttsc fix and ttsc format belong to @ttsc/lint — see Fix & format commands.

Subcommands

Subcommand	Purpose
`ttsc`	Default. Same as `ttsc build`.
`ttsc build`	Build + emit.
`ttsc check`	Type-check only. Same as `ttsc --noEmit`.
`ttsc fix`	Run lint + format autofixes from `@ttsc/lint`, then a no-emit check. One-shot pass; cannot combine with `--watch` or `--emit`.
`ttsc format`	Apply only the format-class lint rules.
`ttsc prepare`	Pre-build every plugin binary into the cache.
`ttsc clean`	Delete the plugin binary cache.
`ttsc version`	Print the CLI version.
`ttsc help`	Print help.

Flags

Flag	Meaning
`-p, --project <file>`	tsconfig file. Same as `--tsconfig`.
`--tsconfig <file>`	tsconfig file.
`--cwd <dir>`	Resolve relative paths against this directory.
`--noEmit`	Type-check only, no file writes.
`--emit`	Force emit even when `tsconfig` sets `noEmit: true`.
`-w, --watch`	Watch source files and re-check on change.
`--preserveWatchOutput`	Don’t clear the screen between watch runs.
`--outDir <dir>`	Override `compilerOptions.outDir`.
`--quiet`	Suppress per-file output (default).
`--verbose`	Print build summary and emitted file paths.
`--binary <path>`	Use a specific tsgo binary instead of the bundled one.
`--cache-dir <dir>`	Plugin binary cache root. Defaults to `node_modules/.ttsc`.

Settings like target, module, strict, lib, declaration, sourceMap, and other classic tsc compilerOptions are read from tsconfig.json, not from CLI flags.

Exit codes

Code	Meaning
0	Success — no errors. Warnings may have been printed.
1	Build failure — type errors, lint errors, or plugin failure.
2	Configuration error — bad `tsconfig.json`, missing plugin, invalid flags.

Plugin cache

The plugin binary cache lives at node_modules/.ttsc/ by default. Override with --cache-dir. Safe to delete at any time (ttsc clean) — binaries get rebuilt on next use.