Architecture

Build pipeline

The lexicon is authored as CSVs and compiled to JavaScript maps; the content script is then bundled with Rollup. No TypeScript — JSDoc supplies the types.

data/*.csv  →  compile-lexicon.js  →  dist/lexicon.js
                                    →  dist/abbreviations.js
                                    →  dist/contractions.js
                                    →  dist/phrases.js

src/content/*.js + dist/*.js  →  Rollup (iife)  →  dist/content-bundle.js

The engine is DOM-free

The conversion core is text-in / text-out. Each stage is a pure function, so it runs anywhere — a browser page, an Electron iframe, a Word taskpane, an Apps Script runtime, a test harness:

• tokenize(text) — words, separators, and contractions (contraction-aware).
• tagWord(word) — the lexical CLAWS7 candidate set from the lexicon.
• convert(word, tokens, idx) — context-aware respelling with full disambiguation.

The convert flow

function convert(word, tokens, idx) {
  const entry = lexicon.get(word.toLowerCase()) ?? contractions.get(word.toLowerCase());
  if (!entry) return word;

  const variants = entry.encoding % 10;      // euspelling count
  if (variants === 0) return word;           // unchanged
  if (variants === 1) return matchCase(word, entry.spellings[0]);

  const i = disambiguate(entry, tokens, idx); // pos.js or semantic/
  return matchCase(word, entry.spellings[i] ?? word);
}

Surfaces around the core

• Chrome extension — content script + service worker; its own PDF.js viewer for PDFs.
• Eupub reader — Electron; injects the engine bundle into each chapter iframe.
• Office converters — Word (Office.js), LibreOffice (Python port), Google Docs (Apps Script port), each validated 35/35 against the reference engine.
• Dictation — an additive authoring path feeding speech through convertText.
• Derived lexicons — PLS for TTS, Morfologik / Harper for grammar checkers.

Testing

• Unit tests — converter, DOM walker, matchCase, individual POS functions.
• Corpus tests — CLAWS7-tagged sentences per ambiguous word, asserting the disambiguation output.
• Cross-engine fixtures — the Python and Apps Script ports are checked against the JS engine.