amazon.js

//This function counts the occurences
function findMostUsedWords(text) {
    const matches = text.reduce((a, b) => {
        a[b] = (a[b] + 1 || 1)
        return a
    }, {})
    const max = Math.max(...Object.values(matches))
    return Object.keys(matches).filter((word) => matches[word] === max)
}
// This function removes the excluded words
function removeExcludedWords(text, wordsToExclude) {
    return text.split(' ').filter((word) => !wordsToExclude.find(wr => wr === word)).map(word => word.toLowerCase())
}

function retrieveMostFrequentlyUsedWords(literatureText, wordsToExclude) {
    const parsedText = literatureText.replace(/[\W_]+/g, ' ')
    const text = removeExcludedWords(parsedText, wordsToExclude)
    return findMostUsedWords(text)
}