hexo-theme-butterfly/layout/includes/third-party/math/mermaid.pug

script.
  (() => {
    const runMermaid = ele => {
      window.loadMermaid = true
      const theme = document.documentElement.getAttribute('data-theme') === 'dark' ? '!{theme.mermaid.theme.dark}' : '!{theme.mermaid.theme.light}'

      ele.forEach((item, index) => {
        const mermaidSrc = item.firstElementChild
        const mermaidThemeConfig = `%%{init:{ 'theme':'${theme}'}}%%\n`
        const mermaidID = `mermaid-${index}`
        const mermaidDefinition = mermaidThemeConfig + mermaidSrc.textContent

        const renderFn = mermaid.render(mermaidID, mermaidDefinition)
        const renderMermaid = svg => {
          mermaidSrc.insertAdjacentHTML('afterend', svg)
        }

        // mermaid v9 and v10 compatibility
        typeof renderFn === 'string' ? renderMermaid(renderFn) : renderFn.then(({ svg }) => renderMermaid(svg))
      })
    }

    const codeToMermaid = () => {
      const codeMermaidEle = document.querySelectorAll('pre > code.mermaid')
      if (codeMermaidEle.length === 0) return

      codeMermaidEle.forEach(ele => {
        const preEle = document.createElement('pre')
        preEle.className = 'mermaid-src'
        preEle.hidden = true
        preEle.textContent = ele.textContent
        const newEle = document.createElement('div')
        newEle.className = 'mermaid-wrap'
        newEle.appendChild(preEle)
        ele.parentNode.replaceWith(newEle)
      })
    }

    const loadMermaid = () => {
      if (!{theme.mermaid.code_write}) codeToMermaid()
      const $mermaid = document.querySelectorAll('#article-container .mermaid-wrap')
      if ($mermaid.length === 0) return

      const runMermaidFn = () => runMermaid($mermaid)
      btf.addGlobalFn('themeChange', runMermaidFn, 'mermaid')
      window.loadMermaid ? runMermaidFn() : btf.getScript('!{url_for(theme.asset.mermaid)}').then(runMermaidFn)
    }

    btf.addGlobalFn('encrypt', loadMermaid, 'mermaid')
    window.pjax ? loadMermaid() : document.addEventListener('DOMContentLoaded', loadMermaid)
  })()