hexo-theme-butterfly/layout/includes/comments/utterances.pug

script.
  if (document.getElementById('utterances-wrap')) {
    function loadUtterances () {
      let ele = document.createElement('script')
      ele.setAttribute('id', 'utterances_comment')
      ele.setAttribute('src', '!{url_for(theme.CDN.utterances)}')
      ele.setAttribute('repo', '!{theme.utterances.repo}')
      ele.setAttribute('issue-term', '!{theme.utterances.issue_term}')
      let nowTheme = document.documentElement.getAttribute('data-theme') === 'dark' ? '#{theme.utterances.dark_theme}' : '#{theme.utterances.light_theme}'
      ele.setAttribute('theme', nowTheme)
      ele.setAttribute('crossorigin', 'anonymous')
      ele.setAttribute('async', 'true')
      document.getElementById('utterances-wrap').insertAdjacentElement('afterbegin',ele)
    }

    function utterancesTheme () {
      if (document.querySelector('.utterances-frame')) {
        const theme = document.documentElement.getAttribute('data-theme') === 'dark' ? '#{theme.utterances.dark_theme}' : '#{theme.utterances.light_theme}'
        const message = {
          type: 'set-theme',
          theme: theme
        };
        const iframe = document.querySelector('.utterances-frame');
        iframe.contentWindow.postMessage(message, 'https://utteranc.es');
      }
    }

    if ('!{defaultComment}' === 'Utterances' || !{theme.comments.load_begin}) {
      loadUtterances()
    }
    else {
      function loadOtherComment () {
        loadUtterances()
      }
    }
  }