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TypeScript Compiler (tsc)

The TypeScript compiler type-checks code and emits JavaScript. On large codebases, tsc can take 30-60 seconds per run, making it the slowest part of most TypeScript validation pipelines.

Native Port

A native port of tsc shows roughly 10x speedup for type checking. The port maintains API compatibility with standard tsc:

# Same commands, faster execution
tsc --noEmit
tsc --watch

The native port is still in development.

Usage

# Type check without emitting
tsc --noEmit

# Watch mode for incremental checking
tsc --watch

# Check specific files
tsc src/index.ts src/utils.ts

Configuration

// tsconfig.json
{
  "compilerOptions": {
    "strict": true,
    "noEmit": true,
    "skipLibCheck": true
  },
  "include": ["src/**/*"]
}

skipLibCheck: true speeds up type checking by skipping declaration files in node_modules. This trades thoroughness for speed.

Agent Considerations

Type checking runs slower than linting, so it fits better as a periodic check rather than a post-edit hook. Run it:

  • Before committing
  • After completing a logical unit of work
  • When the agent reports type-related errors

For per-edit validation, rely on faster tools like Biome for syntax and style issues.

External Resources