- const { effect, source, sub, typed_option } = theme.subtitle
- let subContent = typeof sub === 'string' ? [sub] : (sub || new Array())

script.
  window.typedJSFn = {
    _seq: 0,
    init: str => {
      window.typed = new Typed('#subtitle', Object.assign({
        strings: str,
        startDelay: 300,
        typeSpeed: 150,
        loop: true,
        backSpeed: 50,
      }, !{JSON.stringify(typed_option)}))
    },
    run: subtitleType => {
      const seq = ++window.typedJSFn._seq
      const invoke = () => {
        if (seq === window.typedJSFn._seq) subtitleType()
      }

      if (!{effect}) {
        if (typeof Typed === 'function') invoke()
        else btf.getScript('!{url_for(theme.asset.typed)}').then(invoke)
      } else {
        invoke()
      }
    },
    fetchSubtitle: (fetcher, parser) => {
      const seq = window.typedJSFn._seq
      Promise.resolve()
        .then(fetcher)
        .then(parser)
        .then(({ content, extra = [] }) => {
          if (seq !== window.typedJSFn._seq) return
          typedJSFn.processSubtitle(content, extra)
        })
        .catch(err => {
          if (seq !== window.typedJSFn._seq) return
          console.error('Failed to get the subtitle API:', err)
          typedJSFn.processSubtitle(!{JSON.stringify(subContent)})
        })
    },
    processSubtitle: (content, extraContents = []) => {
      if (!{effect}) {
        const sub = !{JSON.stringify(subContent)}.slice()

        if (extraContents.length > 0) {
          sub.unshift(...extraContents)
        }

        if (typeof content === 'string') {
          sub.unshift(content)
        } else if (Array.isArray(content)) {
          sub.unshift(...content)
        }

        sub.length > 0 && typedJSFn.init(sub)
      } else {
        document.getElementById('subtitle').textContent = typeof content === 'string' ? content :
          (Array.isArray(content) && content.length > 0 ? content[0] : '')
      }
    }
  }
  btf.addGlobalFn('pjaxSendOnce', () => {
    window.typedJSFn._seq++
    typed && typed.destroy()
    window.typed = null
  }, 'typedDestroy')

case source
  when 1
    script.
      function subtitleType () {
        typedJSFn.fetchSubtitle(
          () => fetch('https://v1.hitokoto.cn').then(response => response.json()),
          data => ({ content: data.hitokoto, extra: data.from ? ['出自 ' + data.from] : [] })
        )
      }
      typedJSFn.run(subtitleType)

  when 2
    script.
      function subtitleType () {
        typedJSFn.fetchSubtitle(
          () => fetch('https://v.api.aa1.cn/api/yiyan/index.php').then(response => response.text()),
          data => {
            const reg = /<p>(.*?)<\/p>/g
            const result = reg.exec(data)
            if (result && result[1]) return { content: result[1] }
            throw new Error('Failed to parse the return value of the Yiyan API')
          }
        )
      }
      typedJSFn.run(subtitleType)

  when 3
    script.
      function subtitleType () {
        typedJSFn.fetchSubtitle(
          () => btf.getScript('https://sdk.jinrishici.com/v2/browser/jinrishici.js').then(() =>
            new Promise((resolve, reject) => {
              jinrishici.load(result => {
                if (result && result.data && result.data.content) resolve(result.data.content)
                else reject(new Error('Failed to parse the return value of Jinrishici API'))
              })
            })
          ),
          content => ({ content })
        )
      }
      typedJSFn.run(subtitleType)

  default
    if subContent.length > 0
      script.
        function subtitleType () {
          typedJSFn.processSubtitle(!{JSON.stringify(subContent)})
        }
        typedJSFn.run(subtitleType)