Introduction

kookit is built with TypeScript and Rollup, and serves as the core rendering engine for Koodo Reader. It supports both the Electron desktop client and the React Native (Expo) mobile client.

Supported Formats

Category	Formats
Reflowable books	EPUB, MOBI, AZW3, AZW, TXT, MD, FB2, DOCX, DOC, RTF
Fixed-layout books	PDF, XPS, OXPS, DJVU, DJV, OFD
Comic books	CBZ, CBR, CBT, CB7
Documents	CHM, HTML, XHTML, MHTML, HTM, XML, PPTX, PPT
Others	CACHE (Koodo Reader's cache format)

Building

# Install dependencies
yarn

# Development mode (watch)
yarn dev

# Production build
yarn build

# Clean build artifacts
yarn clean

The build outputs are hardcoded in rollup.config.js and go directly into the host projects:

• Desktop (ES module) → koodo-reader/src/assets/lib/kookit.min.js

Architecture

GeneralRender (src/renders/GeneralRender.ts)
    ├── EpubRender / MobiRender / HtmlRender / Fb2Render
    ├── TxtRender / MdRender / DocxRender / DocRender / RtfRender
    ├── PdfRender / PdfTextRender
    ├── ComicRender / FixedLayoutRender
    ├── PptxRender / XpsRender / OfdRender / DjvuRender
    ├── ChmRender
    └── CacheRender

• BookHelper (src/helpers/bookHelper.ts) is the render factory — it picks the right render class based on the file format.
• GeneralRender.renderTo(element) creates an iframe and injects the content; addTouchEvent wires up touch/selection events for both Android and iOS.
• Fixed-layout formats (PDF, comics, PPTX, XPS, OFD, DJVU) share the same multi-iframe pagination structure.
• src/index.ts is the desktop entry, src/mobile.ts is the mobile entry. The mobile UMD build bundles all dependencies inline; the desktop build treats most dependencies as external (installed by Koodo Reader itself).

Dependencies

Package	Purpose
jszip / fflate	ZIP decompression (multiple engines for compatibility)
7z-wasm	7z archive support (CB7)
js-untar	TAR archive support (CBT)
mammoth	DOCX to HTML conversion
marked	Markdown to HTML conversion
mhtml2html	MHTML to HTML conversion
rangy	Cross-browser text selection and range utilities
chardet	Automatic character encoding detection
chmlib-ts	CHM file parsing (TypeScript port of CHMLib)
liteofd	OFD page rendering to canvas
@web-ppt/core	PPTX / PPT page rendering to SVG
pdf.js	PDF rendering engine, loaded from the host (window.pdfjsLib)

The DjVu, legacy DOC (.doc binary format) and RTF parsers are vendored under src/libs/ and require no external dependencies.

License

This library is distributed under the terms of GNU AGPL v3