project

name	project
description	What typia is, the package family, the JS-descriptor / Go-plugin boundary, the workspace layout, and the canonical commands.

Project Outline

What Typia Is

Typia is a TypeScript transformer library built around one idea: a pure TypeScript type definition should replace the runtime helpers that other tools require schemas, decorators, or hand-written guards for. The compile-time transform reads those types and emits the runtime validator, serializer, schema, or decoder inline.

The packages:

• typia — the user-facing library and typia CLI. Exposes the runtime validators (is, assert, assertGuard, validate), enhanced JSON serde (json.assertParse, json.assertStringify, json.schema), LLM function-calling harness (llm.application, llm.schema, llm.parse, llm.structuredOutput), Protocol Buffer encoder/decoder (protobuf.message, protobuf.assertEncode, protobuf.assertDecode), and the random data generator (random).
• @typia/interface — shared public typings (e.g. IJsonSchema, ILlmSchema, IValidation) consumed by every other package and by user code.
• @typia/utils — runtime, OpenAPI, and LLM utility helpers (e.g. LlmTypeChecker) that live next to but outside the transform.
• @typia/langchain — LangChain.js integration that adapts typia's LLM harness to LangChain tools.
• @typia/mcp — Model Context Protocol integration.
• @typia/vercel — Vercel AI SDK integration.

Downstream projects (@nestia/core, @agentica, @autobe) build on top of typia but are not part of this repository's contract. The exported typia.* surface, the @typia/interface typings, the typia CLI flags, and the ttsc.plugin descriptor shape are public; renaming or removing any of them is a deliberate, separate change.

Architecture

A single Go program under packages/typia/native performs the compile-time transform that emits validators, stringifiers, schemas, and decoders in place of typia.*<T>() call sites. packages/typia registers a Go command package that ttsc (the TypeScript-Go compiler with native plugin support) compiles into a binary on first use through its plugin manifest:

"ttsc": { "plugin": { "transform": "typia/lib/transform" } }

The transform.ts files inside the typia packages are plugin descriptors, not transformers — there is no TypeScript-side transform anymore. The descriptor resolves to the Go entrypoint under native/cmd/; other packages compose on it. Consumers reach the binary through ttsc / ttsx and the published descriptors. ttsc keys each plugin build by content and stores it workspace-wide under node_modules/.cache/ttsc (it walks up to pnpm-workspace.yaml), so every package and test workspace shares one binary; TTSC_CACHE_DIR overrides the location only for suites whose fixture projects live outside the workspace (e.g. tests/test-typia-cli).

Layout

• packages/* — the published packages, including the shared Go plugin under packages/typia/native and its Go unit tests under packages/typia/test (go.work resolves ttsc and its shims through ../node_modules/).
• tests/template — @typia/template, a workspace package that ships the structure fixtures (ObjectSimple, ArrayHierarchical, …) and the TestServant runtime helper consumed by the automated suites.
• tests/test-* — feature-test workspaces:
  • test-typia-schema, test-langchain, test-mcp, test-vercel, test-utils — function-per-file suites under src/features/<group>/<name>.ts, each file exporting one test_<snake_case> function discovered by DynamicExecutor (from @nestia/e2e).
  • test-typia-automated, test-utils-automated — generator-driven matrix suites that cross every typia operation with every @typia/template structure.
  • test-typia-generate — CLI-integration suite for the typia generate command.
  • test-error — call-stripping verification: each call site must be removed from the emitted JS.
• tests/debug — @typia/debug, a one-off ttsx runner for ad-hoc local repros.
• benchmark/ — @typia/benchmark, performance generators with archived results under benchmark/results/**. See .codex/skills/benchmark/SKILL.md.
• website/src/content/docs/** — user-facing MDX guides published at https://typia.io/docs. See .codex/skills/documentation/SKILL.md.
• examples/, experiments/, scripts/, config/ — example sources, tarball staging, repo utilities, and shared build configuration.

Commands

This project requires Node 24.x, pnpm 10.6.4, and Go 1.26+; exact versions are pinned in .github/workflows/ and enforced by CI.

pnpm install
pnpm format
pnpm build
pnpm test

pnpm test runs pnpm test:packages (builds @typia/template, then runs every tests/test-* workspace) followed by pnpm test:toolchain (go test ./... under packages/typia/test). It needs go on PATH. Run pnpm install before go test, or the Go workspace cannot resolve the ttsc shims through ../node_modules/. Test workspaces execute TypeScript sources directly through ttsx, sharing the workspace-local plugin cache under node_modules/.cache/ttsc.

Release-time commands (most contributors skip these): pnpm package:next, pnpm package:latest, pnpm release. pnpm package:tgz stages local tarballs in experiments/tarballs/ for offline testing. See .codex/skills/pull-request/SKILL.md for the release flow.