Uncaught TypeError: Cannot set property 'playbackRate' of null at <anonymous>:1:46

This error occurs when you are trying to set the property 'playbackRate' on a variable that is either undefined or null.

To fix this error, you need to make sure that the variable you are trying to access actually exists and is not null. You can use console.log() to check the value of the variable before attempting to set the property on it.

For example, if you are trying to set the playback rate on a video element, you need to make sure that the video element exists and is not null:

const video = document.querySelector('video');
if (video) {
  video.playbackRate = 2;
}

In this example, we are using the document.querySelector() method to select the first video element on the page. We then check if the video element exists before setting the playback rate to 2.

By checking if the variable is not null before setting the property on it, you can avoid the 'Cannot set property 'playbackRate' of null' error.