如何通过JavaScript CodeWars挑战？

Question

In this challenge I have to replace every "WUB" in the string with a space. If there is more than one "WUB" in a row then I have to replace all of them with a single space. For example, entering "WUBAPPLEWUBWUBBANANAWUBWUBWUBCARROT" would return "APPLE BANANA CARROT" .

Also I have to get rid of heading and trailing spaces at the beginning and end of the string. I was wondering how I could change my code to pass these requirements, I'm still pretty new to JavaScript. Thanks.

function songDecoder(song){
  var regex = /wub/gi;
  song = song.toLowerCase().replace(regex, ' ')
  return song.toUpperCase()
}

Answer 1

You're on right track all you need to do is add a quantifier to match more than one WUB in continuation, and you can also avoid first converting to lowercase and than converting back to uppercase after match as we are using i flag which will take care of case insensitivity

(?:wub)+

 let str = "WUBAPPLEWUBWUBBANANAWUBWUBWUBCARROT" function songDecoder(song){ var regex = /(?:wub)+/gi; song = song.replace(regex, ' ') return song.trim() } console.log(songDecoder(str)) 

Answer 2

As you are new so you need to understand the symbols of using regular expression:

g modifier: global. All matches (don't return after first match)

i modifier: insensitive. Case insensitive match (ignores case of [a-zA-Z])

In your case though i is immaterial as you dont capture [a-zA-Z] .

For input like !@#$? if g modifier is not there regex will return first match ! See here .

If g is there it will return the whole or whatever it can match. See here

let var  = "WUBAPPLEWUBWUBBANANAWUBWUBwubCARROT";
function songDecoder(song){
  var regex = /(?:wub)+/gi;
  song = song.replace(regex, ' ')
  return song.trim()
}

alert(songDecoder(str));