node-stemmer/lib/stemmer.js

A Node.js interface to the Snowball stemming algorithms

import { isNullPointer } from "ffi-rs";
import { Libstemmer } from "./libstemmer.js";
import { UnavailableAlgorithmError } from "./error/unavailable-algorithm-error.js";
import { CharacterEncoding } from "./enum/character-encoding.js";
export default class Stemmer {
    libstemmer;
    stemmer;
    constructor(algorithm, charenc = CharacterEncoding.UTF_8) {
        this.libstemmer = Libstemmer.getLibstemmer();
        this.stemmer = this.libstemmer.sb_stemmer_new(algorithm, charenc);
        if (isNullPointer(this.stemmer)) {
            throw new UnavailableAlgorithmError('Unavailable algorithm');
        }
    }
    static algorithms() {
        const libstemmer = Libstemmer.getLibstemmer();
        const sbStemmerList = libstemmer.sb_stemmer_list();
        let algorithms = [];
        Array.from(sbStemmerList).forEach(item => {
            algorithms.push(item);
        });
        return algorithms;
    }
    stemWord(word) {
        const size = word.length;
        const stem = this.libstemmer.sb_stemmer_stem(this.stemmer, word, size);
        const length = this.libstemmer.sb_stemmer_length(this.stemmer);
        return stem.slice(0, length);
    }
    stemWords(words) {
        let stems = [];
        words.forEach(word => stems.push(this.stemWord(word)));
        return stems;
    }
}