Replace (JIRA) ticket numbers with links in a Google Doc

Code.gs

// This is a script which searches the current
// google doc for ticket numbers (based on a regex)
// and makes them into links. (To JIRA for example).
// It also shortens the links so they only show
// ticket number (removing the https... part)
//
// Edit these 2 variables to fit your needs:
const URL = "https://tracker.mender.io/browse/";
const REGEX = "(AC|ARCHIVE|CFE|CO|COOL|ENT|EV|IBT|INF|MAR|MC|MEN|MENWEB|MM|MPPT|NW|QA|SEC|ZEN)\\-[0-9]{1,5}";

// To use this script, open a Google doc, then;
// Tools -> Script Editor -> (Paste in script) -> Run
// You may be prompted for some permissions

function addLinksToDoc() {
  var body = DocumentApp.getActiveDocument().getBody();
  visit(body);
}

function visit(element) {
  insertLinks(element);
  if (element.getNumChildren === undefined){
    return;
  }
  for (let x = 0; x < element.getNumChildren(); x++) {
    let child = element.getChild(x);
    visit(child);
  }
}

function insertLinks(element) {
  // console.log("Visited: " + element.getType());
  if (element.getType() != "TEXT") {
    return;
  }
  let match = element.findText(REGEX);
  while (match)
  {
    console.log(element.getText());
    let x = match.getStartOffset();
    let y = match.getEndOffsetInclusive();
    let ticket = element.getText().slice(x, y+1);
    console.log("Creating link to: " + ticket);
    element.setLinkUrl(x, y, URL + ticket);

    if (x >= URL.length) {
      if (element.getText().startsWith(URL, x-URL.length)) {
        element.deleteText(x - URL.length, x - 1);
      }
    }

    match = element.findText(REGEX, match);
  }
}