npm install subgenre.js
See how it was made here.
const subgenre = require('./subgenre')
genres = ["otacore", "east coast hip hop", "alternative r&b", "australian pop",'pop']
console.log(subgenre.topLevelGenre('glam metal')) // -> rock
console.log(subgenre.topLevelGenre('qwerty')) // -> __UNKNOWN__
console.log(`Indie Folk is ranked number ${subgenre.allGenres['indie folk']}`) // -> 65
console.log(`The most popular genre is ${subgenre.mostPopularGenre(genres)}`) // -> pop
console.log(`The least popular genre is ${subgenre.leastPopularGenre(genres)}`) // -> otacore