katsu

Katsu is a conjugation practice web app for Japanese verbs and adjectives.

The name is an abbreviation of the Japanese word 活用 (katsuyō), which means conjugation.

Conjugations can be practised for verbs, i-adjectives and na-adjectives.

The following forms can be practised:

• Formal or informal
• Past or non-past
• Positive or negative
• Te-form
• Volitional
• Tai-form
• Tari-form
• Potential
• Imperative / prohibitive
• Conditional
• Passive
• Causative
• Causative-passive

Demo

Use the app at katsu.arthurhoek.nl.

Tech stack

• Angular 22 with standalone components
• Ionic 8 for the UI
• wanakana for kana input and conversion
• ngx-translate for i18n (English, Dutch)
• Installable as a PWA with offline support (Angular service worker)

Development

Requires Node.js 24 or newer (nvm use picks the right version).

git clone https://github.com/ahoek/katsu.git
cd katsu
npm install
npm start

The app is served at http://localhost:4200/.

Tests and lint

npm test    # unit tests (vitest)
npm run lint

Build and deployment

npm run build

The production build is written to dist/browser.

Every push to master is built and deployed to GitHub Pages automatically by the deploy workflow.

Acknowledgements

The word definitions were retrieved from the online dictionary Jisho.

License

MIT