Auto-number each paragraph for a patent application using Web App and Google Docs

AutoNumberTheParagraphs.js

// Eric Draken, 2022, ericdraken.com
// Quick Web App script to auto-number paragraphs in a patent application in Google Docs.
// This will re-number paragraphs in order when run again.
//
// Before:
//     HEADER
// Some fany words
//     HEADER
// More fancy words
// Even more fany words
//
// Afer:
//     HEADER
// [0001] Some fany words
//     HEADER
// [0002] More fancy words
// [0003] Even more fany words
//
function AutoNumberTheParagraphs() {
  var doc = DocumentApp.getActiveDocument();
  var body = doc.getBody();
  var paragraphs = body.getParagraphs();
  var index = 1;
  // e.g. [0001]
  var re = '(\\W|^)\\[[0-9]{4,}\\]\\W{1,}'; // Uses Google RE2 regex
  paragraphs.forEach((p, ind) => {
    // Ignore centered titles in the parent application.
    // There is some bug where "no alignment" is not "Left" but blank.
    if(p.getAlignment() !== DocumentApp.HorizontalAlignment.CENTER && 
      p.getAlignment() !== DocumentApp.HorizontalAlignment.RIGHT){
      var txt = p.getText();
      // Remove existing paragraph numbers
      if(!!txt.match(re)){
        p.replaceText(re, '');
      }
      // Quick check in case this 'paragraph' is just a line break or 'todo' or '...'
      if(txt.length > 10){
        // Add the numbers
        // Google will prepend text with the properties of the preceding paragraph,
        // so shim the inserted text with properties.
        p.editAsText().insertText(0, '[' + String(index++).padStart(4, '0') + '] ').setAttributes(0, 6, p.getAttributes());
      }
    }
  })
}

This is a quick script I wrote. If you can improve it, please do! Thanks in advance.