Clean YouTube Watch Later Videos

youtube_clean_watch_later_videos.js

// Version 2.0.1
// This script will remove all videos from watch later list 
//
// Usage
//
// #1 go to https://www.youtube.com/playlist?list=WL
// #2 run following script in your browser console
(async function() {

  const playlistName = document.querySelector('.metadata-wrapper #container #text')?.textContent || document.querySelector('#text')?.textContent
  if(!playlistName) {
    alert(`Couldn't determine playlist name!`)
    return
  }
  
  if(!confirm(`Are you sure to delete ALL videos from ${playlistName}?`)) {
    return
  }
  
  console.info("start...")
  while(true) {
    const videos = document.querySelectorAll('#primary ytd-playlist-video-renderer')
    if(videos.length == 0) break
    
    for (let videoElement of videos) {
      const videoTitle = videoElement.querySelector('a#video-title')
      console.info(`Remove Video\n`    
        + `  Title: ${videoTitle.innerText}\n`
        + `  URL: ${videoTitle.href}`)

      const actionMenuButton = videoElement.querySelector('#menu #button')
      console.debug("click actionMenuButton", actionMenuButton)
      actionMenuButton.click()

      const removeButton = await untilDefined(() => document.evaluate(
          `//tp-yt-paper-listbox/ytd-menu-service-item-renderer[./tp-yt-paper-item/yt-formatted-string/span[text() = '${playlistName}']]`,
          document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue)
      console.debug("click removeButton", removeButton)
      removeButton.click()
      
      await sleep(200)
    }
  } 
  console.info("done!")

  // === util functions ========================================================
  
  async function sleep (timeout) { 
    return new Promise(res => setTimeout(res, timeout))
  }
  
  async function untilDefined(factory, checkInterval = 100) {
    while (true) {
      const value = factory()
      if (value != null) return value
      await sleep(checkInterval)
    }
  }
})();

Thank you so much, still works in 2023!
This is my fork with prompting the limit of videos to be deleted and randomized delay:
https://gist.github.com/udovichenko/295357dc6b504e4ce3dd540ad6c368a4

YouTube appear to have changed the title document selector for me, so the script breaks when trying to locate the playlist title on line 16:

const playlistName = document.querySelector("#title a").text

Looking at the latest commits in sandorex's fork we can see the new selector that needs to be used as YouTube have changed things around.

Replacing it with something like the following should work, so replace this:

  const playlistName = document.querySelector("#title a").text

  if(!confirm(`Are you sure to delete ALL videos from ${playlistName}?`)) {
    return
  }

with this:

  let playlistName = document.querySelector('.metadata-wrapper #container #text')?.textContent || null;

  let confirmationText = 'Are you sure to delete ALL videos from ' + (!playlistName ? 'this playlist' : playlistName) + '?';

  if (!confirm(confirmationText)) {
    return
  }

I still don't get why they don't add this functionality into the native YouTube experience, its been years and it must be a really common issue once playlists fill up.

thx @othyn, I fixed it

I've been testing my fork for few months that does not require lang specific options and modifications, could use more people trying it, also it's a Violentmonkey script
https://gist.github.com/sandorex/6bdd51ef467a079c87f19ba469a8bc7c
Feel free to take the code if you want

@sandorex thanks a lot, I've updated my script to your provided solution to get rid of language specific configuration.

It seems youtube did something so the script broke a bit, change

const playlistName = document.querySelector('.metadata-wrapper #container #text')?.textContent

to

const playlistName = document.querySelector('#text')?.textContent

The id stayed the same for a while now so im hopeful it wont need more fixing for a while 😄

@sandorex thx a lot, however for me it' works as expected with document.querySelector('.metadata-wrapper #container #text')?.textContent

Weird it works for me now too, it did not work yesterday for some reason