App Script script to change the link text of the link at the current cursor position to the name of the linked Google doc.

entitle_google_docs.js

function onInstall() { 
  onOpen();
}

function onOpen() {
  DocumentApp.getUi()
  .createMenu('Fix links')
  .addItem('Entitle link at cursor', 'entitleAtCursor')
  .addItem('Entitle all links', 'entitleAllLinks')
  .addToUi();
}

function entitleGoogleDoc(url) {
  try {
    var doc = DocumentApp.openByUrl(url);
    return doc.getName();
  } catch (err) {
    return null;
  }
}


function urlStripper(base) {
  return function (url) {
    if (url.length > base.length && url.substr(0, base.length) === base) {
      return url.substr(base.length);
    } else {
      return null;
    }
  }
}

var entitlements = [
  urlStripper("https://democrats.atlassian.net/browse/"),
  entitleGoogleDoc
]

function entitleAtCursor() {
  var c = DocumentApp.getActiveDocument().getCursor();
  var offset = c.getOffset();
  var text = c.getElement().editAsText();
  var url = text.getLinkUrl(offset);
  if (url != null) {
    var beg = findBoundary(text, url, offset, -1);
    var end = findBoundary(text, url, offset, 1);
    entitleLink(text, beg, end, url);
  }
}

function entitleAllLinks() {
  var links = getAllLinks();
  Logger.log('Got ' + links.length + ' links.');
  for (var i = links.length - 1; i >= 0; i--) {
    var link = links[i];
    Logger.log('entitling links[' + i + ']: ' + link.url);
    entitleLink(link.text, link.start, link.end, link.url);
  }
}

function entitleLink(text, start, end, url) {
  var title = titleForURL(url);
  if (title != null) {
    text.deleteText(start, end)
    text.insertText(start, title);
    text.setLinkUrl(start, start + title.length - 1, url);
  }
}

function titleForURL(url) {
  for (var i = 0; i < entitlements.length; i++) {
    var title = entitlements[i](url);
    if (title != null) return title;
  }
  return null;
}

function findBoundary(text, url, offset, step) {
  var o = offset;
  while (o >= 0 && o < text.getText().length && text.getLinkUrl(o) === url) {
    o += step;
  }
  return o - step;
}

function docTitle(url) {
  try {
    var doc = DocumentApp.openByUrl(url);
    return doc.getName();
  } catch (err) {
    return null;
  }
}

function getAllLinks(element, links) {
  element = element || DocumentApp.getActiveDocument().getBody();
  links = links || [];

  if (element.getType() === DocumentApp.ElementType.TEXT) {
    var textObj = element.editAsText();
    var text = element.getText();
    
    var current = null;
 
    for (var i = 0; i < text.length; i++) {
      var url = textObj.getLinkUrl(i);
      if (url) {
        if (current && current.url != url) {
          // Url changed: close current link and save it.
          current.end = i - 1;
          links.push(current);
          current = null;
        }
        
        if (!current) {
          // In a url but no current link: start a new one.
          current = {
            text: element,
            url: url,
            start: i
          }
        }
      } else {
        if (current) {
          // Out of url but we still have a link: close it off and save it.
          current.end = i - 1;
          links.push(current);
          current = null;
        }
      }
    }
    if (current) {
      // End of text and we still have a link: close it off and save it.
      current.end = text.length - 1;
      links.push(current);
      current = null;
    }
 
  } else {
    var n = element.getNumChildren();
    for (var i = 0; i < n; i++) {
      getAllLinks(element.getChild(i), links);
    }
  }

  return links;
}

I'm trying to figure out how to use this - getLinkUrl(offset) to pull the linked URL from a single word in a paragraph of text within a google doc. Can you please offer me a little help?

getLinkUrl(2) retruns - Cannot find method getLinkUrl(number). in Google Apps Script IDE

Thank you for any help you can offer.