I have the same exact problem.
I noticed it after de-activating and deleting/re-installing Woocommerce. I’m not sure if that was the problem that initiated this error, but after deleting Woocommerce a second time, it still doesn’t work.
Will be following this post.
It might have something to do with the new Gutenberg Editor?? Right after seeing the news of the new editor, my theme/customization stopped working.
