advanced-sitemap-generator/src/SitemapStream.js

Easily create XML sitemaps for your website.

const path = require('path');
const rand = require('crypto-random-string');
const os = require('os');
const fs = require('fs');
const escapeUnsafe = require('./helpers/escapeUnsafe');
const msg = require('./helpers/msg-helper');

module.exports = function SitemapStream(options) {
  const tmpPath = path.join(os.tmpdir(), `sitemap_${rand({length: 10})}`);
  msg.info('USING TMP PATH TO SAVE SITEMAP: ' + tmpPath);

  const stream = fs.createWriteStream(tmpPath);
  const urls = [];

  const getPath = () => tmpPath;

  const getPiriorityFromDepth = depth => {
    let pir = 0.5;
    let zeroIndexedDepth = depth - 1;
    if (zeroIndexedDepth === 0) {
      pir = 1;
    } else if (zeroIndexedDepth === 1) {
      pir = 0.9;
    } else if (zeroIndexedDepth === 2) {
      pir = .8;
    } else if (zeroIndexedDepth === 3) {
      pir = .7;
    } else if (zeroIndexedDepth === 4) {
      pir = .6;
    }
    return pir;
  };
  const addURL = url => {
    urls.push(url);
  };

  const initXML = () => {
    stream.write('<?xml version="1.0" encoding="utf-8" standalone="yes" ?>');
    stream.write('\n<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:xhtml="http://www.w3.org/1999/xhtml" >');
  };

  const flushURL = (queueItem) => {
    queueItem.flushed = true;

    const escapedUrl = escapeUnsafe(queueItem.url);

    stream.write(`\n  <url>\n    <loc>${escapedUrl}</loc>`);
    for (let alternativeUrl of queueItem.alternatives) {
      // Skip self refrence alternative URL
      // if(alternativeUrl.value === url.value){
      //   continue;
      // }
      stream.write(`\n    <xhtml:link rel='alternate' hreflang='` + alternativeUrl.lang +
        `' href='` + escapeUnsafe(alternativeUrl.url) + `' />`);
    }
    stream.write(`\n    <changefreq>` + options.changeFreq + `</changefreq>`);
    stream.write(`\n    <priority>` + getPiriorityFromDepth(queueItem.depth) + `</priority>`);
    stream.write(`\n    <lastmod>` + queueItem.lastMod + `</lastmod>`);
    stream.write(`\n  </url>`);
  };
  const flush = () => {
    initXML();

    for (let url of urls) {
      flushURL(url);
    }
  };

  const end = () => {
    stream.write('\n</urlset>');
    stream.end();
  };

  return {
    urls,
    addURL,
    getPath,
    flush,
    end
  };
};