Remove multiple line breaks in a Googe Document using Apps Script

Code.js

function removeMultipleLineBreaks(element) {
  if (!element) {
    element = DocumentApp.getActiveDocument().getBody();
  }
  var parent = element.getParent();
  // Remove empty paragraphs
  if (element.getType() == DocumentApp.ElementType.PARAGRAPH 
      && element.asParagraph().getText().replace(/\s/g, '') == '') {
    if (!(parent.getType() == DocumentApp.ElementType.BODY_SECTION 
         && parent.getChildIndex(element) == parent.getNumChildren() - 1)) {
      element.removeFromParent();
    }
  // Remove duplicate newlines in text
  } else if (element.getType() == DocumentApp.ElementType.TEXT) {
    var text = element.asText();
    var content = text.getText();
    var matches;
    // Remove duplicate carriage returns within text.
    if (matches = content.match(/\r\s*\r/g)) {
      for (var i = matches.length - 1; i >= 0; i--) {
        var match = matches[i];
        var startIndex = content.lastIndexOf(match);
        var endIndexInclusive = startIndex + match.length - 1;
        text.deleteText(startIndex + 1, endIndexInclusive);
      }
    }
    // Grab the text again.
    content = text.getText();
    // Remove carriage returns at the end of the text.
    if (matches = content.match(/\r\s*$/)) {
      var match = matches[0];
      text.deleteText(content.length - match.length, content.length - 1);
    }
    // Remove carriage returns at the start of the text.
    if (matches = content.match(/^\s*\r/)) {
      var match = matches[0];
      text.deleteText(0, match.length - 1);
    }
  // Recursively look in child elements
  } else if (element.getNumChildren) {
    for (var i = element.getNumChildren() - 1; i >= 0; i--) {
      var child = element.getChild(i);
      removeMultipleLineBreaks(child);
    }
  }
}