Docusaurus in-project plugin

plugin.js

module.exports = function (context) {
  const { siteConfig } = context  // Siteconfig is the content of docusaurus.config.js
  const { themeConfig } = siteConfig
  if (!themeConfig.goatcounter) {
    throw new Error(
      'You need to specify `goatcounter` object in `themeConfig` '
      + 'with `code` field in it to use docusaurus-plugin-goatcounter'
    )
  }
  if (!themeConfig.goatcounter.code) {
    throw new Error(
      'You specified the `goatCounter` object in `themeConfig`, '
      + 'but the `code` field was missing. '
    )
  }
  const analyticsDomain = `https://${themeConfig.goatcounter.code}.goatcounter.com`
  return {
    name: 'docusaurus-plugin-goatcounter',
    injectHtmlTags: () => { // Adds additional HTLM to every page
      return {
        headTags: [
          {
            tagName: 'script',
            attributes: {
              async: true,
              src: '//gc.zgo.at/count.js',
              'data-goatcounter': `${analyticsDomain}/count`,
            },
          },
        ],
      }
    },
  }
}