@zirkelc/typecheck

TypeScript type checker for monorepo packages. Runs tsc --noEmit using the TypeScript compiler API and filters out diagnostics from files outside the current package directory.

This solves the problem of internal packages exporting raw .ts files:

Errors in internal dependencies will be reported: When directly exporting TypeScript, type-checking in a dependent package will fail if code in an internal dependency has TypeScript errors. You may find this confusing or problematic in some situations.

Install

pnpm add -D @zirkelc/typecheck

Usage

Add a script to your monorepo packages package.json:

{
  "scripts": {
    "typecheck": "typecheck"
  }
}

Then run in your monorepo packages:

# Uses tsconfig.json by default
pnpm typecheck

# Use a custom tsconfig
pnpm typecheck --project tsconfig.build.json

How it works

1. Reads the tsconfig.json (or --project target) in process.cwd()
2. Creates a ts.Program and collects all diagnostics via ts.getPreEmitDiagnostics()
3. Filters diagnostics: only keeps errors where the source file is inside the current directory
4. Formats remaining errors with colors and code context using ts.formatDiagnosticsWithColorAndContext()
5. Exits with code 1 if local errors exist, 0 otherwise