Architecture Overview

Data flow

JSX → createElement() → JS tree → serde-wasm-bindgen → Rust DocumentTree
    → docxio-ooxml XML → docxio-core ZIP → Uint8Array

┌──────────────┐     ┌──────────────────┐     ┌─────────────────┐
│  JSX / TSX   │ ──► │  JS Object Tree  │ ──► │  Rust via WASM  │
│  components  │     │  (DocumentNode)  │     │  docxio-core    │
└──────────────┘     └──────────────────┘     └────────┬────────┘
                                                       │
                                              ┌────────▼────────┐
                                              │  OOXML XML +    │
                                              │  ZIP packaging  │
                                              │  → Uint8Array   │
                                              └─────────────────┘

Step-by-step

1. JSX authoring -- Developers write documents using JSX syntax with <document>, <paragraph>, <run>, etc.
2. createElement -- Bun/tsc transpiles JSX to docxio/jsx-runtime calls, producing a plain JS object tree.
3. Tree transform -- The transformTree function normalizes the JS tree for the Rust side.
4. FFI boundary -- The tree crosses into WASM via a single serde-wasm-bindgen call (no JSON.stringify overhead).
5. XML generation -- docxio-ooxml generates OOXML XML parts (document.xml, styles.xml, numbering.xml, etc.) using the quick-xml writer API.
6. ZIP packaging -- docxio-core assembles all XML parts plus media files into a .docx ZIP archive.
7. Return -- The ZIP bytes are returned as a Uint8Array to JavaScript.

Package structure

TypeScript packages

Package	Size	Role
docxio	15 KB JS + WASM	Core: JSX runtime, transformer, render functions
@docxio/html	~5 KB	HTML and Markdown export
@docxio/zip	~8 KB	JS-side ZIP assembly for minimal backend
@docxio/bun	~2 KB	Bun build plugin
@docxio/node	native	napi-rs server binding
@docxio/wasm-minimal	441 KB	Minimal WASM binary

Rust crates

docxio-types        → Shared document model (serde + tsify)
    ↑
docxio-ooxml        → OOXML XML generation (quick-xml)
    ↑
docxio-core         → Orchestration: tree → XML → ZIP
    ↑
├── docxio-wasm          → Full WASM binding (920 KB)
├── docxio-wasm-minimal  → Minimal WASM binding (441 KB)
├── docxio-napi          → Native Node.js binding (napi-rs)
├── docxio-cli           → CLI tool (clap)
├── docxio-pdf           → PDF export (planned)
├── docxio-bench         → Benchmarks (criterion)
└── docxio-fuzz          → Fuzz testing

See Rust Crates for detailed crate responsibilities.

Design principles

• Single FFI call -- The entire document tree crosses the WASM boundary once, avoiding per-element overhead.
• No React dependency -- The JSX factory is a simple createElement function. Documents are static trees, not reactive components.
• Layered crates -- Each Rust crate has a single responsibility. docxio-types has no dependencies on XML or ZIP.
• Modular WASM -- The minimal build excludes ZIP, template, and validation code for smaller browser bundles.
• XML safety -- All user text is escaped via quick-xml. No string concatenation for XML generation.