Deno - CORS problem with this function

gistfile1.txt

export const addDocument = async ({
  request,
  response,
}: {
request: any
  response: any
}) => {
  response.headers.set('Access-Control-Allow-Origin', '*')
  console.log("processing POST request")

  const  {
       value : {token, fileName, id, content}
     } = await request.body()

  if (token == "abracadabra") {
        const doc_ = {id: id, fileName: fileName, content: content}
        if (isNotPresent(doc_, documents)) {
            documents.push(doc_)
            console.log("pushing document: " + doc_.fileName)
            response.body = { msg: 'OK' }
            response.status = 200
          } else {
            console.log("duplicate document")
            response.body = { msg: 'file already exists' }
            response.status = 200
          }

      } else {
        response.body = { msg: 'Token does not match' }
        response.status = 400
      }
}