Cloudflare Workers main URL Redirect not working, Params as well

Question

Alief here. I'm trying to use Cloudflare Workers to redirect a subdomain to a different domain, but it's not working : wa.example.com to wa.me/60123456789

And its path, which works well : wa.example.com/WantToBuy to wa.me/60123456789?text=Want%20To%20Buy

Also, I'm unable to remove params (fbclid) from the subdomain in the same script.

The route for this worker is wa.example.com/*

How do I make it work? Thank you in advance.

Here is my full script:

addEventListener('fetch', event => {
  event.respondWith(fetchAndApply(event.request))
})

async function fetchAndApply(request) {

let url = new URL(request.url);
let path = url.pathname;

var yourNumber = "60123456789"
const yourMessage = "'"+path+"'"

  number = yourNumber
  message = yourMessage.match(/(\d+|[a-z]+|([A-Z]([A-Z]+|[a-z]*)))/g).join('%20')

let whatsapp = 'wa.me/' + number + '?text=' + message

return fetch(whatsapp,request);
}

addEventListener('fetch', event => {
  let url = new URL(event.request.url)

  if (url.searchParams.has('fbclid'))
   url.searchParams.delete('fbclid')

  event.respondWith(
    fetch(url, event.request)
  )
})

Answer 1

Several problems here...

number = yourNumber
message = yourMessage.match(/(\d+|[a-z]+|([A-Z]([A-Z]+|[a-z]*)))/g).join('%20')

You should put var or let before these declarations of number and message . Otherwise, you are storing these into global variables, which could affect other requests, which is almost certainly not what you want.

message = yourMessage.match(/(\d+|[a-z]+|([A-Z]([A-Z]+|[a-z]*)))/g).join('%20')

When match() doesn't find any matches, it returns null . When you then call .join() on it, this will throw an exception. Indeed, running your script in the preview generates this error message in the console: Uncaught (in response) TypeError: Cannot read property 'join' of null

This is why your script isn't working when no path is sent -- in that case, there are no matches of the regex.

let whatsapp = 'wa.me/' + number + '?text=' + message

You probably want to add https:// to the beginning of this URL, otherwise it's not valid.

addEventListener('fetch', event => {

Your script uses addEventListener('fetch') more than once, with both listeners producing a result. The first listener that calls respondWith() will "win", so the second listener is ignored, hence why you find it isn't working.