napi-sudachi

napi-rs implementation of Sudachi.rs

TL;DR

Install package

npm install @nikkei/napi-sudachi

Usage

const sudachi = require('@nikkei/napi-sudachi')
const tokenizer = new sudachi.Tokenizer()
const mode = sudachi.SplitMode.c()

const testText = 'すもももももももものうち'
const morphemes = tokenizer.tokenize(testText, mode)

morphemes[0] >>
  {
    surface: 'すもも',
    partOfSpeech: ['名詞', '普通名詞', '一般', '*', '*', '*'],
    normalizedForm: '李',
    dictionaryForm: 'すもも',
    readingForm: 'スモモ',
    dictionaryId: 0,
  }

Setup

Setup must be done the same way as for Sudachi.rs.

• Download the Sudachi dictionary
• Non-dictionary configuration is already included in resources, which is a fork of sudachi.rs/resources

Download a Sudachi Dictionary

You can use yarn setup-dictionary / npm run setup-dictionary to download a dictionary in resources/ directory

Like sudachi.rs/fetch_dictionary.sh, this downloads the latest SudachiDict. You can also pass version and type as arguments.

yarn setup-dictionary 20241021 small
# or
npm run setup-dictionary -- 20241021 small

Config

You can set environment variable for config in sudachi

• SUDACHI_CONFIG_FILE: config.json path
• SUDACHI_RESOURCE_DIR: resources/ path
• SUDACHI_DICT_PATH: dictionary path
• SUDACHI_USER_DICT: user dictionary path (optional, if not set, user_dict will not be configured)

For Developers

based on napi-rs/package-template

Requirements

• the latest Rust
• Node.js
• yarn

Build

After yarn build command, you can see napi-sudachi.[darwin|win32|linux].node file in project root. This is the native addon built from lib.rs.

Test in local

yarn
yarn build
yarn test

CI

With GitHub Actions, each commit and pull request will be built and tested automatically. For the list of supported Node.js versions and operating systems, please refer to .github/workflows/CI.yml.

Release package

Releases are triggered by pushing a semver Git tag.

1. On a release branch, bump the version (updates platform packages via napi-rs hooks):

npm version [<newversion> | major | minor | patch | premajor | preminor | prepatch | prerelease [--preid=<prerelease-id>] | from-git]

2. Open a PR with the version bump and merge it into main.

3. After the merge, tag the merge commit on main and push the tag (must match package.json version, with a v prefix):

git checkout main && git pull
git tag vX.Y.Z
git push origin vX.Y.Z

GitHub actions will do the rest job for you.

WARN: Don't run npm publish manually.

Copyright 2026 Nikkei Inc.