batch-remove-watch-later.js

// Batch-delete videos from YouTube’s “Watch later” playlist
// Paste the following code into a browser console while the playlist is open
// Code based on: https://gist.github.com/astamicu/eb351ce10451f1a51b71a1287d36880f?permalink_comment_id=4087416#gistcomment-4087416
//
// (Suggestions for improvement welcome. My approach for waiting for the .click() to finish, feels hacky.)

const pause = (ms) => new Promise((resolve) => setTimeout(resolve, ms));
async function remove() {
  for (let i=0; i < 100; i++) {
    document.querySelector('#primary button[aria-label="Action menu"]').click();
    await pause(0);
    document.evaluate('//span[contains(text(),"Remove from")]', document, null, 
       XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null).snapshotItem(0).click();
    await pause(500);
  }
  
}
remove();