Polycarpus works as a DJ in the best Berland nightclub, and he often uses dubstep music in his performance. Recently, he has decided to take a couple of old songs and make dubstep remixes from them. Let's assume that a song consists of some number of words. To make the dubstep remix of this song, Polycarpus inserts a certain number of words "WUB…

dubstep.js

function songDecoder(song){
 return song.replace(/(WUB)+/g, " ").trim();
}

1.- Create an array separating the string using the word 'WUB' like separator ,
2.- Iterate over the new array and filter the elements that are not empty
3.- join the new array with an space

1.- var res = song.split('WUB')
2.- res = res.filter( s => {
if( s.legth !== 0 )
return s
} )
3.- res = res.join(' ')

return song.replace(/(WUB)+/g, " ").trim();
//this works