Performance regression in xmlbuilder2

[khromov]

Describe the bug After some performance profiling in our application it appears that xmlbuilder2 is approximately 2-3 times slower than xmlbuilder for our use case (XML sitemaps). Can something be done to get the performance more in-line with the original library?

To Reproduce I'm attaching two test scripts below. When I run them I get these results:

✗ node xmlbuilder.js
Execution time: 3794ms

✗ node xmlbuilder2.js
Execution time: 10706ms

xmlbuilder.js

const builder = require("xmlbuilder");

const articles = [];
for (let i = 0; i < 500000; i += 1) {
  articles.push({
    loc: 'https://example.org',
    changefreq: 'weekly',
    priority: 0.6,
  });
}

const start = new Date();

const obj = {
  urlset: {
    '@xmlns:xsi': 'http://www.w3.org/2001/XMLSchema-instance',
    '@xmlns': 'http://www.sitemaps.org/schemas/sitemap/0.9',
    '@xsi:schemaLocation':
      'http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd',
    url: [...articles],
  },
};

const feed = builder.create(obj, { encoding: 'utf-8' });
const output = feed.end({ pretty: false });

const end = new Date() - start;
console.info('Execution time: %dms', end);

xmlbuilder2.js

const { create } = require('xmlbuilder2');

const articles = [];
for (let i = 0; i < 500000; i += 1) {
  articles.push({
    loc: 'https://example.org',
    changefreq: 'weekly',
    priority: 0.6,
  });
}

const start = new Date();

const obj = {
  urlset: {
    '@xmlns:xsi': 'http://www.w3.org/2001/XMLSchema-instance',
    '@xmlns': 'http://www.sitemaps.org/schemas/sitemap/0.9',
    '@xsi:schemaLocation':
      'http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd',
    url: [...articles],
  },
};

const doc = create(obj).dec({ encoding: 'UTF-8' });
const xml = doc.end({ prettyPrint: false });

const end = new Date() - start;
console.info('Execution time: %dms', end);

Expected behavior Similar performance as the xmlbuilder library.

Version:

• node.js: v14.15.1
• xmlbuilder2 2.4.0
• xmlbuilder 15.1.1