Pure JavaScript implementation of LEFFF lemmatizer.

Part of this readme come from the Python implementation https://github.com/ClaudeCoulombe/FrenchLefffLemmatizer

A French Lemmatizer in JavaScript based on the LEFFF (Lexique des Formes Fléchies du Français / Lexicon of French inflected forms) is a large-scale morphological and syntactic lexicon for French. A lemmatizer returns the lemma or more simply the dictionary entry of a word, In French, the lemmatization of a verb returns this verb to the infinitive and for the other words, the lemmatization returns this word to the masculine singular.

Sagot (2010). The Lefff, a freely available and large-coverage morphological and syntactic lexicon for French. In Proceedings of the 7th international conference on Language Resources and Evaluation (LREC 2010), Istanbul, Turkey. Retrieved from Benoît Sagot Webpage about LEFFF

In this project, we use the morphological lexicon only: .mlex file which has a simple format in CSV (4 fields separated by \t)

LEFFF download hyperlink

Tagset format FRMG - from the ALPAGE project since 2004

npm i node-lefff

const nodeLefff = require('node-lefff');
const nl = await nodeLefff.load();

nl.lem('action') // action
nl.lem('acteur') // acteur
nl.lem('actrices') // acteur
nl.lem('Dleyton') // Dleyton

const nodeLefff = require('node-lefff');
const nl = await nodeLefff.load();
const Stemmer = require('natural/lib/natural/stemmers/stemmer_fr');

const LefffLemmer = new Stemmer();
LefffLemmer.stem = nl.lem;

LefffLemmer.tokenizeAndStem('Mes mémés m\'aimaient mais pas papa'); // ['mémé', 'aimer', 'papa']

• word <String>: Word
• @return <String>: Lemmatized word, or word itself, if no lemma is known

• word <String>: Word
• @return Array<Object>:

   [{
      type: String
      lemma: String // Lemmatized word
      mode: String 
   }, ...]

Learn more about mode and type here:

• mode: https://github.com/Poyoman39/node-lefff/blob/main/src/lefff-3.4.mlex/lefff-tagset-0.1.2.pdf
• type: https://github.com/Poyoman39/node-lefff/blob/main/src/lefff-3.4.mlex/lefff-3.4.mlex

• mode String: mode string returned by nl.infos
• @return Object:

   {
     indicatif: Bool,
     conditionnel: Bool,
     impératif: Bool,
     subjonctif: Bool,
     participe: Bool,
     infinitif: Bool,
     présent: Bool,
     futur: Bool,
     imparfait: Bool,
     passéSimple: Bool,
     passé: Bool,
     premièrePersonne: Bool,
     deuxièmePersonne: Bool,
     troisièmePersonne: Bool,
     masculin: Bool,
     féminin: Bool,
     singulier: Bool,
     pluriel: Bool,
   }