next-sitemap duplicated language in alternate ref path (href)

[boyanhtrai]

Describe the bug
Refer: https://stackoverflow.com/questions/74108508/next-sitemap-duplicated-language-in-alternate-ref-path-href
We have duplicated for '/en' when I config as below
module.exports = {
siteUrl: 'https://www.ora-candle.com'
generateRobotsTxt: true,
i18n: {
locales: ['en', 'vi'],
defaultLocale: 'vi',
},
changefreq: 'monthly',
generateIndexSitemap: false,
alternateRefs: [
{
href: ',
hreflang: 'en',
},
],
};

Result behavior

<url>
        <loc>https://www.ora-candle.com</loc>
        <lastmod>2024-10-24T18:32:12.746Z</lastmod>
        <changefreq>monthly</changefreq>
        <priority>0.7</priority>
        <xhtml:link rel="alternate" hreflang="en" href="https://www.ora-candle.com/en"/>
    </url>
<url>
        <loc>https://www.ora-candle.com/en</loc>
         <lastmod>2024-10-24T18:32:12.748Z</lastmod>
        <changefreq>monthly</changefreq>
        <priority>0.7</priority>
        **<xhtml:link rel="alternate" hreflang="en" href="https://www.ora-candle.com/en/en"/>** ==> error
    </url>

Expected behavior

<url>
        <loc>https://www.ora-candle.com</loc>
        <lastmod>2024-10-24T18:32:12.746Z</lastmod>
        <changefreq>monthly</changefreq>
        <priority>0.7</priority>
        <xhtml:link rel="alternate" hreflang="en" href="https://www.ora-candle.com/en"/>
    </url>
<url>
        <loc>https://www.ora-candle.com/en</loc>
         <lastmod>2024-10-24T18:32:12.748Z</lastmod>
        <changefreq>monthly</changefreq>
        <priority>0.7</priority>
        <xhtml:link rel="alternate" hreflang="en" href="https://www.ora-candle.com/en"/>
    </url>

[chr4ss12]

yeah lookslike bug, I had hard time generating sitemap with correctlocales,

had to resort to this:

const nextConfig = require('./next-i18next.config.js');

const {locales} = nextConfig.i18n;

const pages = [
  'page1',
  'page2'

];

const localizedPages = [
  ...locales.flatMap(locale =>
    pages.map(page => ({
      locale,
      page,
      href: `https://www.random.com/${locale === 'en' ? page : `${locale}/${page}`}`,
    })),
  ),

  ...locales
    .filter(l => l !== 'en')
    .map(locale => ({
      locale,
      page: '',
      href: `https://www.random.com/${locale}`,
    })),
];

const transform = async (config, path) => ({
  loc: path, // => this will be exported as http(s)://<config.siteUrl>/<path>
  changefreq: config.changefreq,
  priority: config.priority,
  lastmod: config.autoLastmod ? new Date().toISOString() : undefined,
  alternateRefs: config.alternateRefs ?? [],
});

module.exports = {
  siteUrl: 'https://www.random.com',
  changefreq: 'daily',
  priority: 0.7,
  sitemapSize: 5000,
  generateRobotsTxt: true,

  // exclude: ['/server-sitemap.xml'],

  alternateRefs: [
    ...nextConfig.i18n.locales
      .map(locale => ({
        href: `https://www.random.com/${locale}`,
        hreflang: locale,
      }))
      .filter(h => h.hreflang !== 'en'),

    {
      href: 'https://www.random.com',
      hreflang: 'en',
    },
  ],

  // Default transformation function
  transform,

  additionalPaths: async config => [
    ...(await Promise.all(
      localizedPages.map(({locale, href, page}) =>
        transform(
          {
            ...config,
            alternateRefs: localizedPages
              .filter(x => x.page === page)
              .map(localizedPage => ({
                href: localizedPage.href,
                hrefIsAbsolute: true,
                hreflang: localizedPage.locale,
              })),
          },
          `${href}`,
        ),
      ),
    )),
  ],
  robotsTxtOptions: {
    policies: [
      {
        userAgent: '*',
        allow: '/',
      },
    ],
    additionalSitemaps: ['https://www.random.com/blog/sitemap.xml'],
  },
};