A high-performance TypeScript .d.ts emitter written in Zig. Native companion to the TypeScript-based @stacksjs/dtsx — same output, significantly faster.

zig-dtsx reimplements the dtsx declaration-generation pipeline in Zig for maximum performance. Output is byte-identical to the TS implementation, so it slots in as a drop-in replacement wherever the compiled binary is available.

Two surfaces ship in one repo:

• CLI (zig-dtsx) — standalone binary, distributable via pantry.
• TS FFI bridge (@stacksjs/zig-dtsx) — a Bun FFI wrapper that loads the shared library and exposes processSource(), processBatch(), etc. for in-process use from JS/TS tooling such as bun-plugin-dtsx.

pantry add zig-dtsx

bun add @stacksjs/zig-dtsx -d

import { processSource, ZIG_AVAILABLE } from '@stacksjs/zig-dtsx'

if (ZIG_AVAILABLE) {
  const dtsOutput = processSource(typescriptSource, true)
  console.log(dtsOutput)
}

Requires Zig to be installed.

# Build optimized release binary
bun run build:zig

# Build debug binary
bun run build:zig-debug

# Run Zig-native tests
bun run test:zig

The Zig implementation mirrors the TypeScript dtsx pipeline:

1. Scanner - Tokenizes TypeScript source into a stream of tokens
2. Extractor - Parses tokens and extracts declaration-relevant constructs (exports, types, interfaces, classes, functions, variables)
3. Emitter - Produces .d.ts output from the extracted declarations

The Zig binary communicates with the Bun runtime via FFI, allowing seamless integration with the existing dtsx ecosystem.

src/
  scanner.zig         tokenizer
  extractors.zig      declaration extraction
  type_inference.zig  type-mapping + isolated-declarations rules
  emitter.zig         .d.ts output
  scan_loop.zig       parser driver
  char_utils.zig      character classification helpers
  types.zig           shared AST/declaration types
  lib.zig             FFI surface (shared library)
  main.zig            CLI entrypoint
  index.ts            Bun FFI wrapper (consumed by JS/TS)
test/
  zig-dtsx.test.ts    bun:test suite against the FFI wrapper
  benchmark.ts        cross-tool perf harness
build.zig             builds both shared lib + CLI

Benchmarked on Apple M3 Pro, macOS (bun 1.3.11, arm64-darwin).

bun run benchmark

Tests validate that the Zig emitter produces identical output to the TypeScript implementation across all shared test fixtures.

# Run via Bun test runner
bun test

# Run Zig-native tests
zig build test

• stacksjs/dtsx — the reference TS implementation
• stacksjs/bun-plugin-dtsx — Bun bundler plugin that will consume this
• zig-utils/zig-regex — sibling project; same release pattern (zig-bump + zig-changelog + pantry publish)

MIT — see LICENSE.md.