A script for a heuristic search for a similar name

fullTextSearch.js

const expect = actual => {
    const toBe = expected => {
        let [a, b] = [actual, expected].map(JSON.stringify);
        if (a !== b) {
            console.error(a + ' should be ' + b);
        }
    };
    return { toBe, toEqual: toBe };
};

class FullTextSearch {

    static getWords(s) {
        return s
            .normalize('NFC')
            .toUpperCase()
            .replace(/(?:\s|[&().,:;/\\<=>[\]{|}~\-\u2010\u2012\u00AD\u2013\u2014\u2043\u2212\uFE58\uFE63\uFF0D])+/g, ' ')
            .split(/ /g)
            .filter(x => !!x);
    }

    // artcles from Germanic/Romance languages, whose match is less important than the rest of the words
    static isArticle = (() => {
        const res = { };
        'a|as|das|de|der|des|die|du|ein|eine|el|la|las|le|les|lo|los|o|os|the|um|uma|umas|un|una|unas|une|uno|unos|uns'
            .match(/[^|]+/g)
            .forEach(s => res[s.toUpperCase()] = true);
        return res
    })();
    
    static getScore(oldWords, newWordCount, newWordPositions) {

        const oldWordCount = oldWords.length;
        let oldLeftPos = 0;
        let score = 0;
        
        // look at every word in an existing string
        for (let oldWord of oldWords) {
            const newLeftPos = newWordPositions[oldWord];
            
            // found a matching word
            if (newLeftPos != null) { 
            
                // find the distance between the word positions
                const newRightPos = newWordCount - newLeftPos - 1;
                const oldRightPos = oldWordCount - oldLeftPos - 1;
                const posDiff = Math.min(
                    Math.abs(newLeftPos - oldLeftPos),
                    Math.abs(newRightPos - oldRightPos));
                    
                // the closer the words are spaced, the higher the score
                score += 1000 - posDiff; 
                
                // rank stoplist word much lower
                if (this.isArticle[oldWord]) {
                    score /= 5;
                }
            }
            oldLeftPos++;
        }
        return score;
    }

    static searchNearestString(oldStrings, newString) {

        // check arguments
        let res = null;
        if (!newString || !oldStrings) {
            return res;
        }
        
        // search the exact match
        for (let oldString of oldStrings) {
            if (oldString === newString) {
                return oldString;
            }
        }            

        // split new string to words
        const newWordPositions = {};
        let newWordCount = 0;
        for (const word of this.getWords(newString)) {
            newWordPositions[word] = newWordCount++;
        }
        
        // find the most relevant string
        let resScore = 0;
        let resWordDiff = 0;
        for (let oldString of oldStrings) {
            const oldWords = this.getWords(oldString);
            const score = this.getScore(oldWords, newWordCount, newWordPositions);
            if (score >= resScore) {
                const wordDiff = Math.abs(oldWords.length - newWordCount);
                if (score > resScore || wordDiff < resWordDiff) {
                    res = oldString;
                    resScore = score;
                    resWordDiff = wordDiff;
                }
            }
        }
        return res;
    }
}

console.clear();

expect(FullTextSearch.searchNearestString(
    ['tmetric - desktop - design', 'tmetric - web'],
    'tmetric - extensions'))
    .toBe('tmetric - web');
expect(FullTextSearch.searchNearestString(
    ['web - tmetric', 'tmetric - web'],
    'tmetric - extensions'))
    .toBe('tmetric - web');
expect(FullTextSearch.searchNearestString(
    ['tmetric - web', 'web - tmetric'],
    'tmetric - extensions'))
    .toBe('tmetric - web');
expect(FullTextSearch.searchNearestString(
    ['Spring Projects - CSV Import - Accounts Payable', 'Acme - Clients - John Doe'],
    'Spring Projects - CSV Import - Accounts Receivable, John Doe'))
    .toBe('Spring Projects - CSV Import - Accounts Payable');
expect(FullTextSearch.searchNearestString(
    ['Design - Ideas', 'Design - Form Responses'],
    'Design - Mark Moe'))
    .toBe('Design - Form Responses');
expect(FullTextSearch.searchNearestString(
    ['The Marketplace', 'TMetric'],
    'The TMetric'))
    .toBe('TMetric');
expect(FullTextSearch.searchNearestString(
    ['TMetric', 'The TMetric'],
    'The TMetric'))
    .toBe('The TMetric');
expect(FullTextSearch.searchNearestString(
    ['TMetric', 'The TMetric'],
    'TMetric'))
    .toBe('TMetric');
expect(FullTextSearch.searchNearestString(
    ['Design: TMetric', 'TMetric Extensions'],
    'TMetric Design'))
    .toBe('Design: TMetric');

expect(FullTextSearch.searchNearestString([], undefined)).toBe(null);
expect(FullTextSearch.searchNearestString(undefined, 'x')).toBe(null);
expect(FullTextSearch.searchNearestString(['a'], 'x')).toBe(null);

expect(FullTextSearch.getWords('TMetric - Design')).toEqual(['TMETRIC', 'DESIGN']);
expect(FullTextSearch.getWords('TMetric: Version 1')).toEqual(['TMETRIC', 'VERSION', '1']);
expect(FullTextSearch.getWords('  TMetric(v1) ')).toEqual(['TMETRIC', 'V1']);
expect(FullTextSearch.getWords('Проєкт Straße', '')).toEqual(['ПРОЄКТ', 'STRASSE']);
expect(FullTextSearch.getWords('TMetric - Design')).toEqual(['TMETRIC', 'DESIGN']);
expect(FullTextSearch.getWords('TMetric - Design')).toEqual(['TMETRIC', 'DESIGN']);

console.log('tests completed');

// Design - Ideas
// Design - Form Responses
// Design - Ashley Webster
// Spring Projects - CSV Import - Accounts Payable
// Spring Projects - Orders
// Spring Projects - CSV Import - Accounts Receivable, Elizabeth Shore
// Circa - Clients - Elizabeth Shore
// Circa - Clients - Stan Edwards
// Circa - Task Management - Backlog
// Circa - Task Management - Stage 2
// Circa - Task Management - Action Items
// Spring Projects - CSV Import - Accounts Payable
// Circa - Clients - Elizabeth Shore
// Spring Projects - CSV Import - Accounts Receivable, Elizabeth Shore