Automatically expand "Show more" on the YouTube video details page

yt-expand_show_more.js

/*
  Automatically expand the 'Show more' button on the 'Video details' page for YouTube videos
  Adapted from: https://stackoverflow.com/a/29754070/493159
  2021.04.28
*/

// Call the below function
waitForElementToDisplay("#toggle-button", function () {
  document.getElementById("toggle-button").click();
}, 1000, 9000);

function waitForElementToDisplay(selector, callback, checkFrequencyInMs, timeoutInMs) {
  var startTimeInMs = Date.now();
  (function loopSearch() {
    if (document.querySelector(selector) != null) {
      callback();
      return;
    } else {
      setTimeout(function () {
        if (timeoutInMs && Date.now() - startTimeInMs > timeoutInMs)
          return;
        loopSearch();
      }, checkFrequencyInMs);
    }
  })();
}