使用javascript下载youtube视频/音频流

因此，我有一个youtube视频/音频流URL，例如：

https://r2---sn-cx1x9-ua8z.googlevideo.com/videoplayback?expire=1578754561&ei=oY0ZXo-WGseM1gbxz73IAg&ip=1.2.3.4&id=o-AN8LZJBbvLne6s8A8IVwnnk2psZvpzQT6fHRCDqPA6iu&itag=251&source=youtube&requiressl=yes&mm=31%2C29&mn=sn-cx1x9-ua8z%2Csn-hgn7rn7y&ms=au%2Crdu&mv=m&mvi=1&pcm2cms=yes&pl=19&initcwndbps=1112500&vprv=1&mime=audio%2Fwebm&gir=yes&clen=3354766&dur=194.861&lmt=1441431906499822&mt=1578732880&fvip=2&keepalive=yes&fexp=23842630&c=WEB&sparams=expire%2Cei%2Cip%2Cid%2Citag%2Csource%2Crequiressl%2Cvprv%2Cmime%2Cgir%2Cclen%2Cdur%2Clmt&lsparams=mm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpcm2cms%2Cpl%2Cinitcwndbps&lsig=AHylml4wRQIgTs579qwl_V5XJrms-WWNp-uiLVENCoA7rKb175F2TgUCIQDiQuorOfGBuiAl3iIdxoTcl8TwSPTjKJTP7HE0XyvKqA%3D%3D&alr=yes&sig=ALgxI2wwRQIgJlSv5BooK4-KKL4J4kkp2RC-NkyScgoySIQWPTfXKgQCIQCE1U8NZWcvrJAl92kKQc4OIKEZTYFtO3imbLg3e6fgwg%3D%3D&cpn=e7UIV_8qKxqkbGKK&cver=2.20200108.07.03&rn=9&rbuf=13039

如何使用Javascript下载它

我不知道这是否有帮助，但HTML是：

<video controls autoplay name="media">
  <source src="That long url like above" type="audio/webm">
</video>

另外，当我右键单击它时，它会显示“另存为”选项，但我正在尝试使用Javascript自动执行此操作