SnowballFilter

Applies Snowball stemming algorithm for multiple languages.

Import

import SnowballFilter from 'dynamosearch/filters/SnowballFilter';

Constructor

new SnowballFilter(options?: { language?: string })

Parameters

• language (string, optional) - Stemmer language (default: 'English')

Supported Languages

Arabic, Armenian, Basque, Catalan, Danish, Dutch, DutchPorter, English, Esperanto, Estonian, Finnish, French, German, Greek, Hindi, Hungarian, Indonesian, Irish, Italian, Lithuanian, Nepali, Norwegian, Polish, Porter, Portuguese, Romanian, Russian, Serbian, Spanish, Swedish, Tamil, Turkish, Yiddish

Examples

English

const filter = new SnowballFilter({ language: 'English' });
const tokens = filter.apply([
  { token: 'running', startOffset: 0, endOffset: 7, position: 0 },
  { token: 'runs', startOffset: 8, endOffset: 12, position: 1 },
  { token: 'runner', startOffset: 13, endOffset: 19, position: 2 },
]);
// [
//   { token: 'run', startOffset: 0, endOffset: 7, position: 0 },
//   { token: 'run', startOffset: 8, endOffset: 12, position: 1 },
//   { token: 'runner', startOffset: 13, endOffset: 19, position: 2 }
// ]

French

const filter = new SnowballFilter({ language: 'French' });
const tokens = filter.apply([
  { token: 'chevaux', startOffset: 0, endOffset: 7, position: 0 },
  { token: 'cheval', startOffset: 8, endOffset: 14, position: 1 },
]);
// [
//   { token: 'cheval', startOffset: 0, endOffset: 7, position: 0 },
//   { token: 'cheval', startOffset: 8, endOffset: 14, position: 1 }
// ]

Spanish

const filter = new SnowballFilter({ language: 'Spanish' });
const tokens = filter.apply([
  { token: 'corriendo', startOffset: 0, endOffset: 9, position: 0 },
  { token: 'correr', startOffset: 10, endOffset: 16, position: 1 },
]);
// [
//   { token: 'corr', startOffset: 0, endOffset: 9, position: 0 },
//   { token: 'corr', startOffset: 10, endOffset: 16, position: 1 }
// ]

Best For

• Multilingual search
• Finding word variants
• Improving recall across languages
• Normalizing word forms

See Also

• PorterStemFilter - For English-only stemming
• FrenchAnalyzer - Uses this filter for French
• SpanishAnalyzer - Uses this filter for Spanish