all-your-images-are-belong-to-us.js

(() => {
  return `
"abort scrolling"
clearInterval(${scrollToTheEnd()});
"total images count"
document.querySelectorAll('.AdaptiveMedia img').length;
`

  function scrollToTheEnd(interval = 800) {
    const theEnd = document.querySelector('#timeline .stream-end')
    const id = setInterval(() => {
      if (document.defaultView.getComputedStyle(theEnd, '').display === 'none') {
        window.scrollTo(0, document.body.scrollHeight)
      } else {
        clearInterval(id)
        downloadAll()
      }
    }, interval)

    return id
  }

  function download(url, name = url.split('/').pop()) {
    return fetch(new Request(url))
      .then(res => res.blob())
      .then(blob => {
        const $a = document.createElement('a')
        $a.href = URL.createObjectURL(blob)
        $a.download = name
        $a.click()
        URL.revokeObjectURL($a.href)
        delete $a
      })
  }

  async function downloadAll(interval = 100) {
    const images = Array.from(document.querySelectorAll('.stream-item .tweet'))
      .map(tweet => {
        const unixtime = parseInt(tweet.querySelector('[data-time-ms]').dataset.timeMs)
        const date = (new Date(unixtime)).toLocaleDateString('ja-JP').replace(/\//g, '-')
        const { dataset: { screenName, tweetId }} = tweet

        return Array.from(tweet.querySelectorAll('.AdaptiveMedia img')).map(({src}, i, {length}) => ({
          url: src,
          name: `${screenName}-${date}-${tweetId}${length ? `-${i+1}` : ''}.${src.split('.').pop()}`,
        }))
      }).flat()

    function wait(msec, func, ...args) {
      return new Promise(result => setTimeout(() => result(func(...args)), msec))
    }

    for (const {url, name} of images) {
      await wait(interval, download, url, name)
    }
  }
})()