JapaneseStopFilter

Removes common Japanese stop words (similar to English stop words filter).

Import

import JapaneseStopFilter from '@dynamosearch/plugin-analysis-kuromoji/filters/JapaneseStopFilter';

Installation

npm install @dynamosearch/plugin-analysis-kuromoji

Constructor

new JapaneseStopFilter(options?: { stopWords?: Set<string> })

Parameters

• stopWords (Set<string>, optional) - Words to remove. Defaults to 118 common Japanese stop words.

Examples

Default Stop Words

const filter = new JapaneseStopFilter();
const tokens = filter.apply([
  { token: 'これ' },
  { token: '素晴らしい' },
  { token: 'です' }
]);
// [
//   { token: '素晴らしい' }
// ]
// 'これ' and 'です' are removed

Custom Stop Words

const filter = new JapaneseStopFilter({
  stopWords: new Set(['の', 'に', 'は', 'を'])
});

Default Stop Words

Based on Apache Lucene's Japanese stopwords:

Common particles and functional words like:

• の, に, は, を, た, が, で, て, と, し, れ, さ
• ある, いる, も, する, から, な, こと, として
• この, その, あの, これ, それ, あれ
• など, まで, もの, こと, ため
• And many more (118 words total)

Best For

• Removing very common words that don't add search value
• Reducing index size
• Focusing on meaningful content

Difference from KuromojiPartOfSpeechStopFilter

TIP

• JapaneseStopFilter: Removes specific words (text-based matching)
• KuromojiPartOfSpeechStopFilter: Removes entire grammatical categories (POS-based)

For most use cases, KuromojiPartOfSpeechStopFilter is more comprehensive and recommended.

See Also

• KuromojiPartOfSpeechStopFilter - For POS-based filtering
• StopFilter - English equivalent