"Naive" Solution for finding related posts on a blog

naiveSort.js

const _ = require('lodash')

const tokenize = string => {
    return string.split(' ').map(w => {
        return w.trim().toLowerCase().replace(/[^a-zA-Z]/g, '')
    }).filter(w => w)
}

const similarPosts = (posts, targetPost) => {

    // split target title
    const titleWords = tokenize(targetPost.title)

    // sort posts by number of common words
    const sorted = posts.sort((p1, p2) => {

        // get array intersection of target title words and
        // post body words. Run for both posts
        const p1_matches = tokenize(p1.content).filter(word => {
            return titleWords.includes(word)
        })
        const p2_matches = tokenize(p2.content).filter(word => {
            return titleWords.includes(word)
        })

        // return difference of intersection length (create descending results)
        return _.uniq(p2_matches).length - _.uniq(p1_matches).length
    })

    // return top 5 matches
    return sorted.slice(0, 5)

}